diff options
| -rw-r--r-- | doc/src/sgml/plsql.sgml | 48 |
1 files changed, 41 insertions, 7 deletions
diff --git a/doc/src/sgml/plsql.sgml b/doc/src/sgml/plsql.sgml index b30bca80f7d..60d6b62be3c 100644 --- a/doc/src/sgml/plsql.sgml +++ b/doc/src/sgml/plsql.sgml @@ -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"> @@ -880,12 +880,11 @@ RETURN <replaceable>expression</replaceable> <title>Conditional Control: IF statements</title> <para> - <function>IF</function> statements let you take action - according to certain conditions. PL/pgSQL has three forms of - IF: IF-THEN, IF-THEN-ELSE, IF-THEN-ELSE IF. NOTE: All - PL/pgSQL IF statements need a corresponding <function>END - IF</function> statement. In ELSE-IF statements you need two: - one for the first IF and one for the second (ELSE IF). + <function>IF</function> statements let you execute commands based on + certain conditions. PL/PgSQL has four forms of IF: IF-THEN, IF-THEN-ELSE, + IF-THEN-ELSE IF, IF-THEN-ELSIF-THEN-ELSE. NOTE: All PL/PgSQL IF statements need + a corresponding <function>END IF</function> clause. With ELSE-IF statements, + you need two: one for the first IF and one for the second (ELSE IF). </para> <variablelist> @@ -979,6 +978,41 @@ END IF; </para> </listitem> </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 < 0 THEN + result := ''negative''; +ELSIF number > 0 THEN + result := ''negative''; +ELSE + -- now it seems to be NULL + result := ''NULL''; +END IF; +</programlisting> + </para> + </listitem> + </varlistentry> + + </variablelist> </sect3> |