Clarify documentation about SQL:2008 variant of LIMIT/OFFSET syntax.

The point that you need parentheses for non-constant expressions apparently
needs to be brought out a bit more clearly, per bug #6315.

diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 15d9b75b59bede312d5b8787bc7484453f598cfb..3fbfda309e268ac53adf3097d9550a06b3acdcc1 100644 (file)
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -1056,17 +1056,19 @@ OFFSET start
 OFFSET start { ROW | ROWS }
 FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } ONLY
 
-    According to the standard, the OFFSET clause must come
-    before the FETCH clause if both are present; but
-    PostgreSQL is laxer and allows either order.
+    In this syntax, to write anything except a simple integer constant for
+    start or 
+    class="parameter">count, you must write parentheses
+    around it.
+    If count is
+    omitted in a FETCH clause, it defaults to 1.
     ROW
     and ROWS as well as FIRST
     and NEXT are noise words that don't influence
-    the effects of these clauses.  In this syntax, when using expressions
-    other than simple constants for start
-    or count, parentheses will be
-    necessary in most cases.  If count is
-    omitted in FETCH, it defaults to 1.
+    the effects of these clauses.
+    According to the standard, the OFFSET clause must come
+    before the FETCH clause if both are present; but
+    PostgreSQL is laxer and allows either order.