Fix (mis)information about NULLIF() SQL function.

Thanks to Tom Lane for pointing it out.

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 492859f56b6243af532fb328aa9b85403f53cbfa..2bfec9272e5aa8411d69e67d89df92549afb24ff 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -45,10 +45,10 @@
      class="parameter">c2 + 5, 0) 
        
        
-    IFNULL(input,non-NULL substitute) 
-    non-NULL 
-    return second argument if first is NULL 
-    IFNULL(c1, 'N/A')
+    NULLIF(input,value) 
+    input or NULL 
+    return NULL if input = value 
+    NULLIF(c1, 'N/A')
        
        
     CASE WHEN expr THEN expr [...] ELSE expr END