From 07c25723dae380a3163981cff1028e7c289e7eb4 Mon Sep 17 00:00:00 2001
From: Bruce Momjian
Date: Mon, 12 Jun 2006 16:45:30 +0000
Subject: Add BY clause to PL/PgSQL FOR loop, to control the iteration
 increment.

Jaime Casanova
---
 doc/src/sgml/plpgsql.sgml | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

(limited to 'doc/src')

diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml
index f0cbbf2896c..60c7593362b 100644
--- a/doc/src/sgml/plpgsql.sgml
+++ b/doc/src/sgml/plpgsql.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.94 2006/05/30 13:40:55 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.95 2006/06/12 16:45:30 momjian Exp $ -->
 
 <chapter id="plpgsql"> 
   <title><application>PL/pgSQL</application> - <acronym>SQL</acronym> Procedural Language</title>
@@ -1975,7 +1975,7 @@ END LOOP;
 
 <synopsis>
 <optional> &lt;&lt;<replaceable>label</replaceable>&gt;&gt; </optional>
-FOR <replaceable>name</replaceable> IN <optional> REVERSE </optional> <replaceable>expression</replaceable> .. <replaceable>expression</replaceable> LOOP
+FOR <replaceable>name</replaceable> IN <optional> REVERSE </optional> <replaceable>expression</replaceable> .. <replaceable>expression</replaceable> <optional> BY <replaceable>expression</replaceable> </optional> LOOP
     <replaceable>statements</replaceable>
 END LOOP <optional> <replaceable>label</replaceable> </optional>;
 </synopsis>
@@ -1988,8 +1988,10 @@ END LOOP <optional> <replaceable>label</replaceable> </optional>;
         definition of the variable name is ignored within the loop).
         The two expressions giving
         the lower and upper bound of the range are evaluated once when entering
-        the loop. The iteration step is normally 1, but is -1 when <literal>REVERSE</> is
-        specified.
+        the loop. If the <literal>BY</> clause isn't specified the iteration 
+        step is 1 otherwise it's the value specified in the <literal>BY</> 
+        clause. If <literal>REVERSE</> is specified then the step value is 
+		considered negative.
        </para>
 
        <para>
@@ -2003,6 +2005,11 @@ END LOOP;
 FOR i IN REVERSE 10..1 LOOP
     -- some computations here
 END LOOP;
+
+FOR i IN REVERSE 10..1 BY 2 LOOP
+    -- some computations here
+    RAISE NOTICE 'i is %', i;
+END LOOP;
 </programlisting>
        </para>
 
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