From f98f6ee0641e87c6ecc2524f5d0a8b54924ffd14 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Wed, 12 Nov 2008 13:09:28 +0000
Subject: array_length() function, and for SQL compatibility also cardinality()
 function as a special case.

This version still has the suspicious behavior of returning null for an
empty array (rather than zero), but this may need a wholesale revision of
empty array behavior, currently under discussion.

Jim Nasby, Robert Haas, Peter Eisentraut
---
 doc/src/sgml/array.sgml | 14 +++++++++++++-
 doc/src/sgml/func.sgml  | 26 +++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 2 deletions(-)

(limited to 'doc/src')

diff --git a/doc/src/sgml/array.sgml b/doc/src/sgml/array.sgml
index 4d762c53d35..08a3ee021d2 100644
--- a/doc/src/sgml/array.sgml
+++ b/doc/src/sgml/array.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.67 2008/10/29 11:24:52 petere Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.68 2008/11/12 13:09:27 petere Exp $ -->
 
 <sect1 id="arrays">
  <title>Arrays</title>
@@ -324,6 +324,18 @@ SELECT array_upper(schedule, 1) FROM sal_emp WHERE name = 'Carol';
 -------------
            2
 (1 row)
+</programlisting>
+
+ <function>array_length</function> will return the length of a specified
+ array dimension:
+
+<programlisting>
+SELECT array_length(schedule, 1) FROM sal_emp WHERE name = 'Carol';
+
+ array_length
+--------------
+            2
+(1 row)
 </programlisting>
  </para>
  </sect2>
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1e329904512..85403e2c9f7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.456 2008/11/07 22:54:41 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.457 2008/11/12 13:09:27 petere Exp $ -->
 
  <chapter id="functions">
   <title>Functions and Operators</title>
@@ -9408,6 +9408,17 @@ SELECT NULLIF(value, '(none)') ...
         <entry><literal>array_fill(7, ARRAY[3], ARRAY[2])</literal></entry>
         <entry><literal>[2:4]={7,7,7}</literal></entry>
        </row>
+       <row>
+        <entry>
+         <literal>
+          <function>array_length</function>(<type>anyarray</type>, <type>int</type>)
+         </literal>
+        </entry>
+        <entry><type>int</type></entry>
+        <entry>returns the length of the requested array dimension</entry>
+        <entry><literal>array_length(array[1,2,3], 1)</literal></entry>
+        <entry><literal>3</literal></entry>
+       </row>
        <row>
         <entry>
          <literal>
@@ -9452,6 +9463,19 @@ SELECT NULLIF(value, '(none)') ...
         <entry><literal>array_upper(ARRAY[1,2,3,4], 1)</literal></entry>
         <entry><literal>4</literal></entry>
        </row>
+       <row>
+        <entry>
+         <literal>
+          <function>cardinality</function>(<type>anyarray</type>)
+         </literal>
+        </entry>
+        <entry><type>int</type></entry>
+        <entry>returns the length of the first dimension of the array
+        (special case of <function>array_length</function> for SQL
+        compatibility)</entry>
+        <entry><literal>cardinality(array[1,2,3])</literal></entry>
+        <entry><literal>3</literal></entry>
+       </row>
        <row>
         <entry>
          <literal>
-- 
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