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ELSEIF PL/PgSQL doc patch.

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Klaus Reger
This commit is contained in:
Bruce Momjian 2001-05-22 13:52:27 +00:00
parent e6ba9213a2
commit fdf067c108
1 changed files with 41 additions and 7 deletions
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48
doc/src/sgml/plsql.sgml
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@ -1,5 +1,5 @@
<!-- <!--
$Header: /cvsroot/pgsql/doc/src/sgml/Attic/plsql.sgml,v 2.32 2001/05/17 21:50:16 petere Exp $ $Header: /cvsroot/pgsql/doc/src/sgml/Attic/plsql.sgml,v 2.33 2001/05/22 13:52:27 momjian Exp $
--> -->
<chapter id="plpgsql"> <chapter id="plpgsql">
@ -880,12 +880,11 @@ RETURN <replaceable>expression</replaceable>
<title>Conditional Control: IF statements</title> <title>Conditional Control: IF statements</title>
<para> <para>
<function>IF</function> statements let you take action <function>IF</function> statements let you execute commands based on
according to certain conditions. PL/pgSQL has three forms of certain conditions. PL/PgSQL has four forms of IF: IF-THEN, IF-THEN-ELSE,
IF: IF-THEN, IF-THEN-ELSE, IF-THEN-ELSE IF. NOTE: All IF-THEN-ELSE IF, IF-THEN-ELSIF-THEN-ELSE. NOTE: All PL/PgSQL IF statements need
PL/pgSQL IF statements need a corresponding <function>END a corresponding <function>END IF</function> clause. With ELSE-IF statements,
IF</function> statement. In ELSE-IF statements you need two: you need two: one for the first IF and one for the second (ELSE IF).
one for the first IF and one for the second (ELSE IF).
</para> </para>
<variablelist> <variablelist>
@ -979,6 +978,41 @@ END IF;
</para> </para>
</listitem> </listitem>
</varlistentry> </varlistentry>
<varlistentry>
<term>
IF-THEN-ELSIF-ELSE
</term>
<listitem>
<para>
IF-THEN-ELSIF-ELSE allows you test multiple conditions
in one statement. Internally it is handled as nested
IF-THEN-ELSE-IF-THEN commands. The optional ELSE
branch is executed when none of the conditions are met.
</para>
<para>
Here is an example:
</para>
<programlisting>
IF number = 0 THEN
result := ''zero'';
ELSIF number &lt; 0 THEN
result := ''negative'';
ELSIF number &gt; 0 THEN
result := ''negative'';
ELSE
-- now it seems to be NULL
result := ''NULL'';
END IF;
</programlisting>
</para>
</listitem>
</varlistentry>
</variablelist> </variablelist>
</sect3> </sect3>