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- For enum types (described in <a class="xref" href="datatype-enum.html" title="8.7. Enumerated Types">Section 8.7</a>),
- there are several functions that allow cleaner programming without
- hard-coding particular values of an enum type.
- These are listed in <a class="xref" href="functions-enum.html#FUNCTIONS-ENUM-TABLE" title="Table 9.33. Enum Support Functions">Table 9.33</a>. The examples
- assume an enum type created as:
-
- </p><pre class="programlisting">
- CREATE TYPE rainbow AS ENUM ('red', 'orange', 'yellow', 'green', 'blue', 'purple');
- </pre><p>
-
- </p><div class="table" id="FUNCTIONS-ENUM-TABLE"><p class="title"><strong>Table 9.33. Enum Support Functions</strong></p><div class="table-contents"><table class="table" summary="Enum Support Functions" border="1"><colgroup><col /><col /><col /><col /></colgroup><thead><tr><th>Function</th><th>Description</th><th>Example</th><th>Example Result</th></tr></thead><tbody><tr><td>
- <a id="id-1.5.8.15.3.2.2.1.1.1" class="indexterm"></a>
- <code class="literal">enum_first(anyenum)</code>
- </td><td>Returns the first value of the input enum type</td><td><code class="literal">enum_first(null::rainbow)</code></td><td><code class="literal">red</code></td></tr><tr><td>
- <a id="id-1.5.8.15.3.2.2.2.1.1" class="indexterm"></a>
- <code class="literal">enum_last(anyenum)</code>
- </td><td>Returns the last value of the input enum type</td><td><code class="literal">enum_last(null::rainbow)</code></td><td><code class="literal">purple</code></td></tr><tr><td>
- <a id="id-1.5.8.15.3.2.2.3.1.1" class="indexterm"></a>
- <code class="literal">enum_range(anyenum)</code>
- </td><td>Returns all values of the input enum type in an ordered array</td><td><code class="literal">enum_range(null::rainbow)</code></td><td><code class="literal">{red,orange,yellow,green,blue,purple}</code></td></tr><tr><td rowspan="3"><code class="literal">enum_range(anyenum, anyenum)</code></td><td rowspan="3">
- Returns the range between the two given enum values, as an ordered
- array. The values must be from the same enum type. If the first
- parameter is null, the result will start with the first value of
- the enum type.
- If the second parameter is null, the result will end with the last
- value of the enum type.
- </td><td><code class="literal">enum_range('orange'::rainbow, 'green'::rainbow)</code></td><td><code class="literal">{orange,yellow,green}</code></td></tr><tr><td><code class="literal">enum_range(NULL, 'green'::rainbow)</code></td><td><code class="literal">{red,orange,yellow,green}</code></td></tr><tr><td><code class="literal">enum_range('orange'::rainbow, NULL)</code></td><td><code class="literal">{orange,yellow,green,blue,purple}</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
- Notice that except for the two-argument form of <code class="function">enum_range</code>,
- these functions disregard the specific value passed to them; they care
- only about its declared data type. Either null or a specific value of
- the type can be passed, with the same result. It is more common to
- apply these functions to a table column or function argument than to
- a hardwired type name as suggested by the examples.
- </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="functions-datetime.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="functions.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="functions-geometry.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">9.9. Date/Time Functions and Operators </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> 9.11. Geometric Functions and Operators</td></tr></table></div></body></html>
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