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  1. <?xml version="1.0" encoding="UTF-8" standalone="no"?>

  2. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>9.8. Data Type Formatting Functions</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><link rel="prev" href="functions-matching.html" title="9.7. Pattern Matching" /><link rel="next" href="functions-datetime.html" title="9.9. Date/Time Functions and Operators" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">9.8. Data Type Formatting Functions</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="functions-matching.html" title="9.7. Pattern Matching">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="functions.html" title="Chapter 9. Functions and Operators">Up</a></td><th width="60%" align="center">Chapter 9. Functions and Operators</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 12.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="functions-datetime.html" title="9.9. Date/Time Functions and Operators">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="FUNCTIONS-FORMATTING"><div class="titlepage"><div><div><h2 class="title" style="clear: both">9.8. Data Type Formatting Functions</h2></div></div></div><a id="id-1.5.8.13.2" class="indexterm"></a><p>

  3.     The <span class="productname">PostgreSQL</span> formatting functions

  4.     provide a powerful set of tools for converting various data types

  5.     (date/time, integer, floating point, numeric) to formatted strings

  6.     and for converting from formatted strings to specific data types.

  7.     <a class="xref" href="functions-formatting.html#FUNCTIONS-FORMATTING-TABLE" title="Table 9.24. Formatting Functions">Table 9.24</a> lists them.

  8.     These functions all follow a common calling convention: the first

  9.     argument is the value to be formatted and the second argument is a

  10.     template that defines the output or input format.

  11.    </p><div class="table" id="FUNCTIONS-FORMATTING-TABLE"><p class="title"><strong>Table 9.24. Formatting Functions</strong></p><div class="table-contents"><table class="table" summary="Formatting Functions" border="1"><colgroup><col /><col /><col /><col /></colgroup><thead><tr><th>Function</th><th>Return Type</th><th>Description</th><th>Example</th></tr></thead><tbody><tr><td>

  12.          <a id="id-1.5.8.13.4.2.2.1.1.1" class="indexterm"></a>

  13.          <code class="literal"><code class="function">to_char(<code class="type">timestamp</code>, <code class="type">text</code>)</code></code>

  14.         </td><td><code class="type">text</code></td><td>convert time stamp to string</td><td><code class="literal">to_char(current_timestamp, 'HH12:MI:SS')</code></td></tr><tr><td><code class="literal"><code class="function">to_char(<code class="type">interval</code>, <code class="type">text</code>)</code></code></td><td><code class="type">text</code></td><td>convert interval to string</td><td><code class="literal">to_char(interval '15h 2m 12s', 'HH24:MI:SS')</code></td></tr><tr><td><code class="literal"><code class="function">to_char(<code class="type">int</code>, <code class="type">text</code>)</code></code></td><td><code class="type">text</code></td><td>convert integer to string</td><td><code class="literal">to_char(125, '999')</code></td></tr><tr><td><code class="literal"><code class="function">to_char</code>(<code class="type">double precision</code>,

  15.         <code class="type">text</code>)</code></td><td><code class="type">text</code></td><td>convert real/double precision to string</td><td><code class="literal">to_char(125.8::real, '999D9')</code></td></tr><tr><td><code class="literal"><code class="function">to_char(<code class="type">numeric</code>, <code class="type">text</code>)</code></code></td><td><code class="type">text</code></td><td>convert numeric to string</td><td><code class="literal">to_char(-125.8, '999D99S')</code></td></tr><tr><td>

  16.          <a id="id-1.5.8.13.4.2.2.6.1.1" class="indexterm"></a>

  17.          <code class="literal"><code class="function">to_date(<code class="type">text</code>, <code class="type">text</code>)</code></code>

  18.         </td><td><code class="type">date</code></td><td>convert string to date</td><td><code class="literal">to_date('05 Dec 2000', 'DD Mon YYYY')</code></td></tr><tr><td>

  19.          <a id="id-1.5.8.13.4.2.2.7.1.1" class="indexterm"></a>

  20.          <code class="literal"><code class="function">to_number(<code class="type">text</code>, <code class="type">text</code>)</code></code>

  21.         </td><td><code class="type">numeric</code></td><td>convert string to numeric</td><td><code class="literal">to_number('12,454.8-', '99G999D9S')</code></td></tr><tr><td>

  22.          <a id="id-1.5.8.13.4.2.2.8.1.1" class="indexterm"></a>

  23.          <code class="literal"><code class="function">to_timestamp(<code class="type">text</code>, <code class="type">text</code>)</code></code>

  24.         </td><td><code class="type">timestamp with time zone</code></td><td>convert string to time stamp</td><td><code class="literal">to_timestamp('05 Dec 2000', 'DD Mon YYYY')</code></td></tr></tbody></table></div></div><br class="table-break" /><div class="note"><h3 class="title">Note</h3><p>

  25.      There is also a single-argument <code class="function">to_timestamp</code>

  26.      function; see <a class="xref" href="functions-datetime.html#FUNCTIONS-DATETIME-TABLE" title="Table 9.31. Date/Time Functions">Table 9.31</a>.

  27.     </p></div><div class="tip"><h3 class="title">Tip</h3><p>

  28.      <code class="function">to_timestamp</code> and <code class="function">to_date</code>

  29.      exist to handle input formats that cannot be converted by

  30.      simple casting.  For most standard date/time formats, simply casting the

  31.      source string to the required data type works, and is much easier.

  32.      Similarly, <code class="function">to_number</code> is unnecessary for standard numeric

  33.      representations.

  34.     </p></div><p>

  35.     In a <code class="function">to_char</code> output template string, there are certain

  36.     patterns that are recognized and replaced with appropriately-formatted

  37.     data based on the given value.  Any text that is not a template pattern is

  38.     simply copied verbatim.  Similarly, in an input template string (for the

  39.     other functions), template patterns identify the values to be supplied by

  40.     the input data string.  If there are characters in the template string

  41.     that are not template patterns, the corresponding characters in the input

  42.     data string are simply skipped over (whether or not they are equal to the

  43.     template string characters).

  44.    </p><p>

  45.    <a class="xref" href="functions-formatting.html#FUNCTIONS-FORMATTING-DATETIME-TABLE" title="Table 9.25. Template Patterns for Date/Time Formatting">Table 9.25</a> shows the

  46.    template patterns available for formatting date and time values.

  47.   </p><div class="table" id="FUNCTIONS-FORMATTING-DATETIME-TABLE"><p class="title"><strong>Table 9.25. Template Patterns for Date/Time Formatting</strong></p><div class="table-contents"><table class="table" summary="Template Patterns for Date/Time Formatting" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Pattern</th><th>Description</th></tr></thead><tbody><tr><td><code class="literal">HH</code></td><td>hour of day (01-12)</td></tr><tr><td><code class="literal">HH12</code></td><td>hour of day (01-12)</td></tr><tr><td><code class="literal">HH24</code></td><td>hour of day (00-23)</td></tr><tr><td><code class="literal">MI</code></td><td>minute (00-59)</td></tr><tr><td><code class="literal">SS</code></td><td>second (00-59)</td></tr><tr><td><code class="literal">MS</code></td><td>millisecond (000-999)</td></tr><tr><td><code class="literal">US</code></td><td>microsecond (000000-999999)</td></tr><tr><td><code class="literal">SSSS</code></td><td>seconds past midnight (0-86399)</td></tr><tr><td><code class="literal">AM</code>, <code class="literal">am</code>,

  48.         <code class="literal">PM</code> or <code class="literal">pm</code></td><td>meridiem indicator (without periods)</td></tr><tr><td><code class="literal">A.M.</code>, <code class="literal">a.m.</code>,

  49.         <code class="literal">P.M.</code> or <code class="literal">p.m.</code></td><td>meridiem indicator (with periods)</td></tr><tr><td><code class="literal">Y,YYY</code></td><td>year (4 or more digits) with comma</td></tr><tr><td><code class="literal">YYYY</code></td><td>year (4 or more digits)</td></tr><tr><td><code class="literal">YYY</code></td><td>last 3 digits of year</td></tr><tr><td><code class="literal">YY</code></td><td>last 2 digits of year</td></tr><tr><td><code class="literal">Y</code></td><td>last digit of year</td></tr><tr><td><code class="literal">IYYY</code></td><td>ISO 8601 week-numbering year (4 or more digits)</td></tr><tr><td><code class="literal">IYY</code></td><td>last 3 digits of ISO 8601 week-numbering year</td></tr><tr><td><code class="literal">IY</code></td><td>last 2 digits of ISO 8601 week-numbering year</td></tr><tr><td><code class="literal">I</code></td><td>last digit of ISO 8601 week-numbering year</td></tr><tr><td><code class="literal">BC</code>, <code class="literal">bc</code>,

  50.         <code class="literal">AD</code> or <code class="literal">ad</code></td><td>era indicator (without periods)</td></tr><tr><td><code class="literal">B.C.</code>, <code class="literal">b.c.</code>,

  51.         <code class="literal">A.D.</code> or <code class="literal">a.d.</code></td><td>era indicator (with periods)</td></tr><tr><td><code class="literal">MONTH</code></td><td>full upper case month name (blank-padded to 9 chars)</td></tr><tr><td><code class="literal">Month</code></td><td>full capitalized month name (blank-padded to 9 chars)</td></tr><tr><td><code class="literal">month</code></td><td>full lower case month name (blank-padded to 9 chars)</td></tr><tr><td><code class="literal">MON</code></td><td>abbreviated upper case month name (3 chars in English, localized lengths vary)</td></tr><tr><td><code class="literal">Mon</code></td><td>abbreviated capitalized month name (3 chars in English, localized lengths vary)</td></tr><tr><td><code class="literal">mon</code></td><td>abbreviated lower case month name (3 chars in English, localized lengths vary)</td></tr><tr><td><code class="literal">MM</code></td><td>month number (01-12)</td></tr><tr><td><code class="literal">DAY</code></td><td>full upper case day name (blank-padded to 9 chars)</td></tr><tr><td><code class="literal">Day</code></td><td>full capitalized day name (blank-padded to 9 chars)</td></tr><tr><td><code class="literal">day</code></td><td>full lower case day name (blank-padded to 9 chars)</td></tr><tr><td><code class="literal">DY</code></td><td>abbreviated upper case day name (3 chars in English, localized lengths vary)</td></tr><tr><td><code class="literal">Dy</code></td><td>abbreviated capitalized day name (3 chars in English, localized lengths vary)</td></tr><tr><td><code class="literal">dy</code></td><td>abbreviated lower case day name (3 chars in English, localized lengths vary)</td></tr><tr><td><code class="literal">DDD</code></td><td>day of year (001-366)</td></tr><tr><td><code class="literal">IDDD</code></td><td>day of ISO 8601 week-numbering year (001-371; day 1 of the year is Monday of the first ISO week)</td></tr><tr><td><code class="literal">DD</code></td><td>day of month (01-31)</td></tr><tr><td><code class="literal">D</code></td><td>day of the week, Sunday (<code class="literal">1</code>) to Saturday (<code class="literal">7</code>)</td></tr><tr><td><code class="literal">ID</code></td><td>ISO 8601 day of the week, Monday (<code class="literal">1</code>) to Sunday (<code class="literal">7</code>)</td></tr><tr><td><code class="literal">W</code></td><td>week of month (1-5) (the first week starts on the first day of the month)</td></tr><tr><td><code class="literal">WW</code></td><td>week number of year (1-53) (the first week starts on the first day of the year)</td></tr><tr><td><code class="literal">IW</code></td><td>week number of ISO 8601 week-numbering year (01-53; the first Thursday of the year is in week 1)</td></tr><tr><td><code class="literal">CC</code></td><td>century (2 digits) (the twenty-first century starts on 2001-01-01)</td></tr><tr><td><code class="literal">J</code></td><td>Julian Day (integer days since November 24, 4714 BC at midnight UTC)</td></tr><tr><td><code class="literal">Q</code></td><td>quarter</td></tr><tr><td><code class="literal">RM</code></td><td>month in upper case Roman numerals (I-XII; I=January)</td></tr><tr><td><code class="literal">rm</code></td><td>month in lower case Roman numerals (i-xii; i=January)</td></tr><tr><td><code class="literal">TZ</code></td><td>upper case time-zone abbreviation

  52.          (only supported in <code class="function">to_char</code>)</td></tr><tr><td><code class="literal">tz</code></td><td>lower case time-zone abbreviation

  53.          (only supported in <code class="function">to_char</code>)</td></tr><tr><td><code class="literal">TZH</code></td><td>time-zone hours</td></tr><tr><td><code class="literal">TZM</code></td><td>time-zone minutes</td></tr><tr><td><code class="literal">OF</code></td><td>time-zone offset from UTC

  54.          (only supported in <code class="function">to_char</code>)</td></tr></tbody></table></div></div><br class="table-break" /><p>

  55.     Modifiers can be applied to any template pattern to alter its

  56.     behavior.  For example, <code class="literal">FMMonth</code>

  57.     is the <code class="literal">Month</code> pattern with the

  58.     <code class="literal">FM</code> modifier.

  59.     <a class="xref" href="functions-formatting.html#FUNCTIONS-FORMATTING-DATETIMEMOD-TABLE" title="Table 9.26. Template Pattern Modifiers for Date/Time Formatting">Table 9.26</a> shows the

  60.     modifier patterns for date/time formatting.

  61.    </p><div class="table" id="FUNCTIONS-FORMATTING-DATETIMEMOD-TABLE"><p class="title"><strong>Table 9.26. Template Pattern Modifiers for Date/Time Formatting</strong></p><div class="table-contents"><table class="table" summary="Template Pattern Modifiers for Date/Time Formatting" border="1"><colgroup><col /><col /><col /></colgroup><thead><tr><th>Modifier</th><th>Description</th><th>Example</th></tr></thead><tbody><tr><td><code class="literal">FM</code> prefix</td><td>fill mode (suppress leading zeroes and padding blanks)</td><td><code class="literal">FMMonth</code></td></tr><tr><td><code class="literal">TH</code> suffix</td><td>upper case ordinal number suffix</td><td><code class="literal">DDTH</code>, e.g., <code class="literal">12TH</code></td></tr><tr><td><code class="literal">th</code> suffix</td><td>lower case ordinal number suffix</td><td><code class="literal">DDth</code>, e.g., <code class="literal">12th</code></td></tr><tr><td><code class="literal">FX</code> prefix</td><td>fixed format global option (see usage notes)</td><td><code class="literal">FX Month DD Day</code></td></tr><tr><td><code class="literal">TM</code> prefix</td><td>translation mode (print localized day and month names based on

  62.          <a class="xref" href="runtime-config-client.html#GUC-LC-TIME">lc_time</a>)</td><td><code class="literal">TMMonth</code></td></tr><tr><td><code class="literal">SP</code> suffix</td><td>spell mode (not implemented)</td><td><code class="literal">DDSP</code></td></tr></tbody></table></div></div><br class="table-break" /><p>

  63.     Usage notes for date/time formatting:

  64. 

  65.     </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>

  66.        <code class="literal">FM</code> suppresses leading zeroes and trailing blanks

  67.        that would otherwise be added to make the output of a pattern be

  68.        fixed-width.  In <span class="productname">PostgreSQL</span>,

  69.        <code class="literal">FM</code> modifies only the next specification, while in

  70.        Oracle <code class="literal">FM</code> affects all subsequent

  71.        specifications, and repeated <code class="literal">FM</code> modifiers

  72.        toggle fill mode on and off.

  73.       </p></li><li class="listitem"><p>

  74.        <code class="literal">TM</code> does not include trailing blanks.

  75.        <code class="function">to_timestamp</code> and <code class="function">to_date</code> ignore

  76.        the <code class="literal">TM</code> modifier.

  77.       </p></li><li class="listitem"><p>

  78.        <code class="function">to_timestamp</code> and <code class="function">to_date</code>

  79.        skip multiple blank spaces at the beginning of the input string and

  80.        around date and time values unless the <code class="literal">FX</code> option is used.  For example,

  81.        <code class="literal">to_timestamp(' 2000    JUN', 'YYYY MON')</code> and

  82.        <code class="literal">to_timestamp('2000 - JUN', 'YYYY-MON')</code> work, but

  83.        <code class="literal">to_timestamp('2000    JUN', 'FXYYYY MON')</code> returns an error

  84.        because <code class="function">to_timestamp</code> expects only a single space.

  85.        <code class="literal">FX</code> must be specified as the first item in

  86.        the template.

  87.       </p></li><li class="listitem"><p>

  88.        A separator (a space or non-letter/non-digit character) in the template string of

  89.        <code class="function">to_timestamp</code> and <code class="function">to_date</code>

  90.        matches any single separator in the input string or is skipped,

  91.        unless the <code class="literal">FX</code> option is used.

  92.        For example, <code class="literal">to_timestamp('2000JUN', 'YYYY///MON')</code> and

  93.        <code class="literal">to_timestamp('2000/JUN', 'YYYY MON')</code> work, but

  94.        <code class="literal">to_timestamp('2000//JUN', 'YYYY/MON')</code>

  95.        returns an error because the number of separators in the input string

  96.        exceeds the number of separators in the template.

  97.       </p><p>

  98.        If <code class="literal">FX</code> is specified, a separator in the template string

  99.        matches exactly one character in the input string.  But note that the

  100.        input string character is not required to be the same as the separator from the template string.

  101.        For example, <code class="literal">to_timestamp('2000/JUN', 'FXYYYY MON')</code>

  102.        works, but <code class="literal">to_timestamp('2000/JUN', 'FXYYYY  MON')</code>

  103.        returns an error because the second space in the template string consumes

  104.        the letter <code class="literal">J</code> from the input string.

  105.       </p></li><li class="listitem"><p>

  106.        A <code class="literal">TZH</code> template pattern can match a signed number.

  107.        Without the <code class="literal">FX</code> option, minus signs may be ambiguous,

  108.        and could be interpreted as a separator.

  109.        This ambiguity is resolved as follows:  If the number of separators before

  110.        <code class="literal">TZH</code> in the template string is less than the number of

  111.        separators before the minus sign in the input string, the minus sign

  112.        is interpreted as part of <code class="literal">TZH</code>.

  113.        Otherwise, the minus sign is considered to be a separator between values.

  114.        For example, <code class="literal">to_timestamp('2000 -10', 'YYYY TZH')</code> matches

  115.        <code class="literal">-10</code> to <code class="literal">TZH</code>, but

  116.        <code class="literal">to_timestamp('2000 -10', 'YYYY  TZH')</code>

  117.        matches <code class="literal">10</code> to <code class="literal">TZH</code>.

  118.       </p></li><li class="listitem"><p>

  119.        Ordinary text is allowed in <code class="function">to_char</code>

  120.        templates and will be output literally.  You can put a substring

  121.        in double quotes to force it to be interpreted as literal text

  122.        even if it contains template patterns.  For example, in

  123.        <code class="literal">'"Hello Year "YYYY'</code>, the <code class="literal">YYYY</code>

  124.        will be replaced by the year data, but the single <code class="literal">Y</code> in <code class="literal">Year</code>

  125.        will not be.

  126.        In <code class="function">to_date</code>, <code class="function">to_number</code>,

  127.        and <code class="function">to_timestamp</code>, literal text and double-quoted

  128.        strings result in skipping the number of characters contained in the

  129.        string; for example <code class="literal">"XX"</code> skips two input characters

  130.        (whether or not they are <code class="literal">XX</code>).

  131.       </p><div class="tip"><h3 class="title">Tip</h3><p>

  132.           Prior to <span class="productname">PostgreSQL</span> 12, it was possible to

  133.           skip arbitrary text in the input string using non-letter or non-digit

  134.           characters. For example,

  135.           <code class="literal">to_timestamp('2000y6m1d', 'yyyy-MM-DD')</code> used to

  136.           work.  Now you can only use letter characters for this purpose.  For example,

  137.           <code class="literal">to_timestamp('2000y6m1d', 'yyyytMMtDDt')</code> and

  138.           <code class="literal">to_timestamp('2000y6m1d', 'yyyy"y"MM"m"DD"d"')</code>

  139.           skip <code class="literal">y</code>, <code class="literal">m</code>, and

  140.           <code class="literal">d</code>.

  141.         </p></div></li><li class="listitem"><p>

  142.        If you want to have a double quote in the output you must

  143.        precede it with a backslash, for example <code class="literal">'\"YYYY

  144.        Month\"'</code>. 

  145.        Backslashes are not otherwise special outside of double-quoted

  146.        strings.  Within a double-quoted string, a backslash causes the

  147.        next character to be taken literally, whatever it is (but this

  148.        has no special effect unless the next character is a double quote

  149.        or another backslash).

  150.       </p></li><li class="listitem"><p>

  151.        In <code class="function">to_timestamp</code> and <code class="function">to_date</code>,

  152.        if the year format specification is less than four digits, e.g.

  153.        <code class="literal">YYY</code>, and the supplied year is less than four digits,

  154.        the year will be adjusted to be nearest to the year 2020, e.g.

  155.        <code class="literal">95</code> becomes 1995.

  156.       </p></li><li class="listitem"><p>

  157.        In <code class="function">to_timestamp</code> and <code class="function">to_date</code>,

  158.        the <code class="literal">YYYY</code> conversion has a restriction when

  159.        processing years with more than 4 digits. You must

  160.        use some non-digit character or template after <code class="literal">YYYY</code>,

  161.        otherwise the year is always interpreted as 4 digits. For example

  162.        (with the year 20000):

  163.        <code class="literal">to_date('200001131', 'YYYYMMDD')</code> will be

  164.        interpreted as a 4-digit year; instead use a non-digit

  165.        separator after the year, like

  166.        <code class="literal">to_date('20000-1131', 'YYYY-MMDD')</code> or

  167.        <code class="literal">to_date('20000Nov31', 'YYYYMonDD')</code>.

  168.       </p></li><li class="listitem"><p>

  169.        In <code class="function">to_timestamp</code> and <code class="function">to_date</code>,

  170.        the <code class="literal">CC</code> (century) field is accepted but ignored

  171.        if there is a <code class="literal">YYY</code>, <code class="literal">YYYY</code> or

  172.        <code class="literal">Y,YYY</code> field. If <code class="literal">CC</code> is used with

  173.        <code class="literal">YY</code> or <code class="literal">Y</code> then the result is

  174.        computed as that year in the specified century.  If the century is

  175.        specified but the year is not, the first year of the century

  176.        is assumed.

  177.       </p></li><li class="listitem"><p>

  178.        In <code class="function">to_timestamp</code> and <code class="function">to_date</code>,

  179.        weekday names or numbers (<code class="literal">DAY</code>, <code class="literal">D</code>,

  180.        and related field types) are accepted but are ignored for purposes of

  181.        computing the result.  The same is true for quarter

  182.        (<code class="literal">Q</code>) fields.

  183.       </p></li><li class="listitem"><p>

  184.        In <code class="function">to_timestamp</code> and <code class="function">to_date</code>,

  185.        an ISO 8601 week-numbering date (as distinct from a Gregorian date)

  186.        can be specified in one of two ways:

  187.        </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem"><p>

  188.           Year, week number, and weekday:  for

  189.           example <code class="literal">to_date('2006-42-4', 'IYYY-IW-ID')</code>

  190.           returns the date <code class="literal">2006-10-19</code>.

  191.           If you omit the weekday it is assumed to be 1 (Monday).

  192.          </p></li><li class="listitem"><p>

  193.           Year and day of year:  for example <code class="literal">to_date('2006-291',

  194.           'IYYY-IDDD')</code> also returns <code class="literal">2006-10-19</code>.

  195.          </p></li></ul></div><p>

  196.       </p><p>

  197.        Attempting to enter a date using a mixture of ISO 8601 week-numbering

  198.        fields and Gregorian date fields is nonsensical, and will cause an

  199.        error.  In the context of an ISO 8601 week-numbering year, the

  200.        concept of a <span class="quote">“<span class="quote">month</span>”</span> or <span class="quote">“<span class="quote">day of month</span>”</span> has no

  201.        meaning.  In the context of a Gregorian year, the ISO week has no

  202.        meaning.

  203.       </p><div class="caution"><h3 class="title">Caution</h3><p>

  204.         While <code class="function">to_date</code> will reject a mixture of

  205.         Gregorian and ISO week-numbering date

  206.         fields, <code class="function">to_char</code> will not, since output format

  207.         specifications like <code class="literal">YYYY-MM-DD (IYYY-IDDD)</code> can be

  208.         useful.  But avoid writing something like <code class="literal">IYYY-MM-DD</code>;

  209.         that would yield surprising results near the start of the year.

  210.         (See <a class="xref" href="functions-datetime.html#FUNCTIONS-DATETIME-EXTRACT" title="9.9.1. EXTRACT, date_part">Section 9.9.1</a> for more

  211.         information.)

  212.        </p></div></li><li class="listitem"><p>

  213.        In <code class="function">to_timestamp</code>, millisecond

  214.        (<code class="literal">MS</code>) or microsecond (<code class="literal">US</code>)

  215.        fields are used as the

  216.        seconds digits after the decimal point. For example

  217.        <code class="literal">to_timestamp('12.3', 'SS.MS')</code> is not 3 milliseconds,

  218.        but 300, because the conversion treats it as 12 + 0.3 seconds.

  219.        So, for the format <code class="literal">SS.MS</code>, the input values

  220.        <code class="literal">12.3</code>, <code class="literal">12.30</code>,

  221.        and <code class="literal">12.300</code> specify the

  222.        same number of milliseconds. To get three milliseconds, one must write

  223.        <code class="literal">12.003</code>, which the conversion treats as

  224.        12 + 0.003 = 12.003 seconds.

  225.       </p><p>

  226.        Here is a more

  227.        complex example:

  228.        <code class="literal">to_timestamp('15:12:02.020.001230', 'HH24:MI:SS.MS.US')</code>

  229.        is 15 hours, 12 minutes, and 2 seconds + 20 milliseconds +

  230.        1230 microseconds = 2.021230 seconds.

  231.       </p></li><li class="listitem"><p>

  232.         <code class="function">to_char(..., 'ID')</code>'s day of the week numbering

  233.         matches the <code class="function">extract(isodow from ...)</code> function, but

  234.         <code class="function">to_char(..., 'D')</code>'s does not match

  235.         <code class="function">extract(dow from ...)</code>'s day numbering.

  236.       </p></li><li class="listitem"><p>

  237.         <code class="function">to_char(interval)</code> formats <code class="literal">HH</code> and

  238.         <code class="literal">HH12</code> as shown on a 12-hour clock, for example zero hours

  239.         and 36 hours both output as <code class="literal">12</code>, while <code class="literal">HH24</code>

  240.         outputs the full hour value, which can exceed 23 in

  241.         an <code class="type">interval</code> value.

  242.       </p></li></ul></div><p>

  243.    </p><p>

  244.    <a class="xref" href="functions-formatting.html#FUNCTIONS-FORMATTING-NUMERIC-TABLE" title="Table 9.27. Template Patterns for Numeric Formatting">Table 9.27</a> shows the

  245.    template patterns available for formatting numeric values.

  246.   </p><div class="table" id="FUNCTIONS-FORMATTING-NUMERIC-TABLE"><p class="title"><strong>Table 9.27. Template Patterns for Numeric Formatting</strong></p><div class="table-contents"><table class="table" summary="Template Patterns for Numeric Formatting" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Pattern</th><th>Description</th></tr></thead><tbody><tr><td><code class="literal">9</code></td><td>digit position (can be dropped if insignificant)</td></tr><tr><td><code class="literal">0</code></td><td>digit position (will not be dropped, even if insignificant)</td></tr><tr><td><code class="literal">.</code> (period)</td><td>decimal point</td></tr><tr><td><code class="literal">,</code> (comma)</td><td>group (thousands) separator</td></tr><tr><td><code class="literal">PR</code></td><td>negative value in angle brackets</td></tr><tr><td><code class="literal">S</code></td><td>sign anchored to number (uses locale)</td></tr><tr><td><code class="literal">L</code></td><td>currency symbol (uses locale)</td></tr><tr><td><code class="literal">D</code></td><td>decimal point (uses locale)</td></tr><tr><td><code class="literal">G</code></td><td>group separator (uses locale)</td></tr><tr><td><code class="literal">MI</code></td><td>minus sign in specified position (if number &lt; 0)</td></tr><tr><td><code class="literal">PL</code></td><td>plus sign in specified position (if number &gt; 0)</td></tr><tr><td><code class="literal">SG</code></td><td>plus/minus sign in specified position</td></tr><tr><td><code class="literal">RN</code></td><td>Roman numeral (input between 1 and 3999)</td></tr><tr><td><code class="literal">TH</code> or <code class="literal">th</code></td><td>ordinal number suffix</td></tr><tr><td><code class="literal">V</code></td><td>shift specified number of digits (see notes)</td></tr><tr><td><code class="literal">EEEE</code></td><td>exponent for scientific notation</td></tr></tbody></table></div></div><br class="table-break" /><p>

  247.     Usage notes for numeric formatting:

  248. 

  249.     </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>

  250.        <code class="literal">0</code> specifies a digit position that will always be printed,

  251.        even if it contains a leading/trailing zero.  <code class="literal">9</code> also

  252.        specifies a digit position, but if it is a leading zero then it will

  253.        be replaced by a space, while if it is a trailing zero and fill mode

  254.        is specified then it will be deleted.  (For <code class="function">to_number()</code>,

  255.        these two pattern characters are equivalent.)

  256.       </p></li><li class="listitem"><p>

  257.        The pattern characters <code class="literal">S</code>, <code class="literal">L</code>, <code class="literal">D</code>,

  258.        and <code class="literal">G</code> represent the sign, currency symbol, decimal point,

  259.        and thousands separator characters defined by the current locale

  260.        (see <a class="xref" href="runtime-config-client.html#GUC-LC-MONETARY">lc_monetary</a>

  261.        and <a class="xref" href="runtime-config-client.html#GUC-LC-NUMERIC">lc_numeric</a>).  The pattern characters period

  262.        and comma represent those exact characters, with the meanings of

  263.        decimal point and thousands separator, regardless of locale.

  264.       </p></li><li class="listitem"><p>

  265.        If no explicit provision is made for a sign

  266.        in <code class="function">to_char()</code>'s pattern, one column will be reserved for

  267.        the sign, and it will be anchored to (appear just left of) the

  268.        number.  If <code class="literal">S</code> appears just left of some <code class="literal">9</code>'s,

  269.        it will likewise be anchored to the number.

  270.       </p></li><li class="listitem"><p>

  271.        A sign formatted using <code class="literal">SG</code>, <code class="literal">PL</code>, or

  272.        <code class="literal">MI</code> is not anchored to

  273.        the number; for example,

  274.        <code class="literal">to_char(-12, 'MI9999')</code> produces <code class="literal">'-  12'</code>

  275.        but <code class="literal">to_char(-12, 'S9999')</code> produces <code class="literal">'  -12'</code>.

  276.        (The Oracle implementation does not allow the use of

  277.        <code class="literal">MI</code> before <code class="literal">9</code>, but rather

  278.        requires that <code class="literal">9</code> precede

  279.        <code class="literal">MI</code>.)

  280.       </p></li><li class="listitem"><p>

  281.        <code class="literal">TH</code> does not convert values less than zero

  282.        and does not convert fractional numbers.

  283.       </p></li><li class="listitem"><p>

  284.        <code class="literal">PL</code>, <code class="literal">SG</code>, and

  285.        <code class="literal">TH</code> are <span class="productname">PostgreSQL</span>

  286.        extensions.

  287.       </p></li><li class="listitem"><p>

  288.        In <code class="function">to_number</code>, if non-data template patterns such

  289.        as <code class="literal">L</code> or <code class="literal">TH</code> are used, the

  290.        corresponding number of input characters are skipped, whether or not

  291.        they match the template pattern, unless they are data characters

  292.        (that is, digits, sign, decimal point, or comma).  For

  293.        example, <code class="literal">TH</code> would skip two non-data characters.

  294.       </p></li><li class="listitem"><p>

  295.        <code class="literal">V</code> with <code class="function">to_char</code>

  296.        multiplies the input values by

  297.        <code class="literal">10^<em class="replaceable"><code>n</code></em></code>, where

  298.        <em class="replaceable"><code>n</code></em> is the number of digits following

  299.        <code class="literal">V</code>.  <code class="literal">V</code> with

  300.        <code class="function">to_number</code> divides in a similar manner.

  301.        <code class="function">to_char</code> and <code class="function">to_number</code>

  302.        do not support the use of

  303.        <code class="literal">V</code> combined with a decimal point

  304.        (e.g., <code class="literal">99.9V99</code> is not allowed).

  305.       </p></li><li class="listitem"><p>

  306.        <code class="literal">EEEE</code> (scientific notation) cannot be used in

  307.        combination with any of the other formatting patterns or

  308.        modifiers other than digit and decimal point patterns, and must be at the end of the format string

  309.        (e.g., <code class="literal">9.99EEEE</code> is a valid pattern).

  310.       </p></li></ul></div><p>

  311.    </p><p>

  312.     Certain modifiers can be applied to any template pattern to alter its

  313.     behavior.  For example, <code class="literal">FM99.99</code>

  314.     is the <code class="literal">99.99</code> pattern with the

  315.     <code class="literal">FM</code> modifier.

  316.     <a class="xref" href="functions-formatting.html#FUNCTIONS-FORMATTING-NUMERICMOD-TABLE" title="Table 9.28. Template Pattern Modifiers for Numeric Formatting">Table 9.28</a> shows the

  317.     modifier patterns for numeric formatting.

  318.    </p><div class="table" id="FUNCTIONS-FORMATTING-NUMERICMOD-TABLE"><p class="title"><strong>Table 9.28. Template Pattern Modifiers for Numeric Formatting</strong></p><div class="table-contents"><table class="table" summary="Template Pattern Modifiers for Numeric Formatting" border="1"><colgroup><col /><col /><col /></colgroup><thead><tr><th>Modifier</th><th>Description</th><th>Example</th></tr></thead><tbody><tr><td><code class="literal">FM</code> prefix</td><td>fill mode (suppress trailing zeroes and padding blanks)</td><td><code class="literal">FM99.99</code></td></tr><tr><td><code class="literal">TH</code> suffix</td><td>upper case ordinal number suffix</td><td><code class="literal">999TH</code></td></tr><tr><td><code class="literal">th</code> suffix</td><td>lower case ordinal number suffix</td><td><code class="literal">999th</code></td></tr></tbody></table></div></div><br class="table-break" /><p>

  319.    <a class="xref" href="functions-formatting.html#FUNCTIONS-FORMATTING-EXAMPLES-TABLE" title="Table 9.29. to_char Examples">Table 9.29</a> shows some

  320.    examples of the use of the <code class="function">to_char</code> function.

  321.   </p><div class="table" id="FUNCTIONS-FORMATTING-EXAMPLES-TABLE"><p class="title"><strong>Table 9.29. <code class="function">to_char</code> Examples</strong></p><div class="table-contents"><table class="table" summary="to_char Examples" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Expression</th><th>Result</th></tr></thead><tbody><tr><td><code class="literal">to_char(current_timestamp, 'Day, DD  HH12:MI:SS')</code></td><td><code class="literal">'Tuesday  , 06  05:39:18'</code></td></tr><tr><td><code class="literal">to_char(current_timestamp, 'FMDay, FMDD  HH12:MI:SS')</code></td><td><code class="literal">'Tuesday, 6  05:39:18'</code></td></tr><tr><td><code class="literal">to_char(-0.1, '99.99')</code></td><td><code class="literal">'  -.10'</code></td></tr><tr><td><code class="literal">to_char(-0.1, 'FM9.99')</code></td><td><code class="literal">'-.1'</code></td></tr><tr><td><code class="literal">to_char(-0.1, 'FM90.99')</code></td><td><code class="literal">'-0.1'</code></td></tr><tr><td><code class="literal">to_char(0.1, '0.9')</code></td><td><code class="literal">' 0.1'</code></td></tr><tr><td><code class="literal">to_char(12, '9990999.9')</code></td><td><code class="literal">'    0012.0'</code></td></tr><tr><td><code class="literal">to_char(12, 'FM9990999.9')</code></td><td><code class="literal">'0012.'</code></td></tr><tr><td><code class="literal">to_char(485, '999')</code></td><td><code class="literal">' 485'</code></td></tr><tr><td><code class="literal">to_char(-485, '999')</code></td><td><code class="literal">'-485'</code></td></tr><tr><td><code class="literal">to_char(485, '9 9 9')</code></td><td><code class="literal">' 4 8 5'</code></td></tr><tr><td><code class="literal">to_char(1485, '9,999')</code></td><td><code class="literal">' 1,485'</code></td></tr><tr><td><code class="literal">to_char(1485, '9G999')</code></td><td><code class="literal">' 1 485'</code></td></tr><tr><td><code class="literal">to_char(148.5, '999.999')</code></td><td><code class="literal">' 148.500'</code></td></tr><tr><td><code class="literal">to_char(148.5, 'FM999.999')</code></td><td><code class="literal">'148.5'</code></td></tr><tr><td><code class="literal">to_char(148.5, 'FM999.990')</code></td><td><code class="literal">'148.500'</code></td></tr><tr><td><code class="literal">to_char(148.5, '999D999')</code></td><td><code class="literal">' 148,500'</code></td></tr><tr><td><code class="literal">to_char(3148.5, '9G999D999')</code></td><td><code class="literal">' 3 148,500'</code></td></tr><tr><td><code class="literal">to_char(-485, '999S')</code></td><td><code class="literal">'485-'</code></td></tr><tr><td><code class="literal">to_char(-485, '999MI')</code></td><td><code class="literal">'485-'</code></td></tr><tr><td><code class="literal">to_char(485, '999MI')</code></td><td><code class="literal">'485 '</code></td></tr><tr><td><code class="literal">to_char(485, 'FM999MI')</code></td><td><code class="literal">'485'</code></td></tr><tr><td><code class="literal">to_char(485, 'PL999')</code></td><td><code class="literal">'+485'</code></td></tr><tr><td><code class="literal">to_char(485, 'SG999')</code></td><td><code class="literal">'+485'</code></td></tr><tr><td><code class="literal">to_char(-485, 'SG999')</code></td><td><code class="literal">'-485'</code></td></tr><tr><td><code class="literal">to_char(-485, '9SG99')</code></td><td><code class="literal">'4-85'</code></td></tr><tr><td><code class="literal">to_char(-485, '999PR')</code></td><td><code class="literal">'&lt;485&gt;'</code></td></tr><tr><td><code class="literal">to_char(485, 'L999')</code></td><td><code class="literal">'DM 485'</code></td></tr><tr><td><code class="literal">to_char(485, 'RN')</code></td><td><code class="literal">'        CDLXXXV'</code></td></tr><tr><td><code class="literal">to_char(485, 'FMRN')</code></td><td><code class="literal">'CDLXXXV'</code></td></tr><tr><td><code class="literal">to_char(5.2, 'FMRN')</code></td><td><code class="literal">'V'</code></td></tr><tr><td><code class="literal">to_char(482, '999th')</code></td><td><code class="literal">' 482nd'</code></td></tr><tr><td><code class="literal">to_char(485, '"Good number:"999')</code></td><td><code class="literal">'Good number: 485'</code></td></tr><tr><td><code class="literal">to_char(485.8, '"Pre:"999" Post:" .999')</code></td><td><code class="literal">'Pre: 485 Post: .800'</code></td></tr><tr><td><code class="literal">to_char(12, '99V999')</code></td><td><code class="literal">' 12000'</code></td></tr><tr><td><code class="literal">to_char(12.4, '99V999')</code></td><td><code class="literal">' 12400'</code></td></tr><tr><td><code class="literal">to_char(12.45, '99V9')</code></td><td><code class="literal">' 125'</code></td></tr><tr><td><code class="literal">to_char(0.0004859, '9.99EEEE')</code></td><td><code class="literal">' 4.86e-04'</code></td></tr></tbody></table></div></div><br class="table-break" /></div><div 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