From 1aab783b59d56af304cd652d2036ba45769122ec Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Sun, 23 Sep 2001 03:39:01 +0000
Subject: [PATCH] Implement TODO item:
* Change LIMIT val,val to offset,limit to match MySQL
Documentation updates too.
---
doc/TODO | 8 ++++----
doc/src/sgml/ref/select.sgml | 20 ++++++++++++--------
doc/src/sgml/sql.sgml | 5 +++--
src/backend/parser/gram.y | 6 +++---
4 files changed, 22 insertions(+), 17 deletions(-)
diff --git a/doc/TODO b/doc/TODO
index 963c17618eb..e7053aae281 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -74,10 +74,10 @@ TYPES
o Allow nulls in arrays
o Allow arrays to be ORDER'ed
o fix array handling in ECPG
-BINARY DATA
+lfBINARY DATA
o -Add non-large-object binary field (already exists -- bytea)
o -Make binary interface for TOAST columns (base64)
- o Improve vacuum of large objects (/contrib/vacuumlo)
+ o Improve vacuum of large objects, like /contrib/vacuumlo
o Add security checking for large objects
o Make file in/out interface for TOAST columns, similar to large object
interface (force out-of-line storage and no compression)
@@ -105,7 +105,7 @@ INDEXES
* Allow CREATE INDEX zman_index ON test (date_trunc( 'day', zman ) datetime_ops)
fails index can't store constant parameters
* Add FILLFACTOR to index creation
-* Order duplicate index entries by tid
+* Order duplicate index entries by tid for faster heap lookups
* -Re-enable partial indexes
* -Prevent pg_attribute from having duplicate oids for indexes (Tom)
* Allow inherited tables to inherit index, UNIQUE constraint, and primary
@@ -124,7 +124,7 @@ INDEXES
non-consecutive keys or OR clauses, so fewer heap accesses
* Allow SELECT * FROM tab WHERE int2col = 4 to use int2col index, int8,
float4, numeric/decimal too [optimizer]
-* Use indexes with CIDR '<<' (contains) operator
+* -Use indexes with CIDR '<<' (contains) operator
* Allow LIKE indexing optimization for non-ASCII locales
* Be smarter about insertion of already-ordered data into btree index
* -Gather more accurate dispersion statistics using indexes (Tom)
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 2e1e552f264..e8dc02498ca 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/select.sgml,v 1.46 2001/09/14 10:28:09 ishii Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/select.sgml,v 1.47 2001/09/23 03:39:01 momjian Exp $
Postgres documentation
-->
@@ -29,7 +29,8 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
[ { UNION | INTERSECT | EXCEPT [ ALL ] } <replaceable class="PARAMETER">select</replaceable> ]
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
[ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
- [ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } [ { OFFSET | , } <replaceable class="PARAMETER">start</replaceable> ]]
+ [ LIMIT [ <replaceable class="PARAMETER">start</replaceable> , ] { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
+ [ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
where <replaceable class="PARAMETER">from_item</replaceable> can be:
@@ -613,7 +614,8 @@ SELECT name FROM distributors ORDER BY code;
<synopsis>
<replaceable class="PARAMETER">table_query</replaceable> UNION [ ALL ] <replaceable class="PARAMETER">table_query</replaceable>
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
- [ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } [ { OFFSET | , } <replaceable class="PARAMETER">start</replaceable> ]]
+ [ LIMIT [ <replaceable class="PARAMETER">start</replaceable> , ] { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
+ [ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
</synopsis>
where
@@ -662,7 +664,8 @@ SELECT name FROM distributors ORDER BY code;
<synopsis>
<replaceable class="PARAMETER">table_query</replaceable> INTERSECT [ ALL ] <replaceable class="PARAMETER">table_query</replaceable>
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
- [ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } [ { OFFSET | , } <replaceable class="PARAMETER">start</replaceable> ]]
+ [ LIMIT [ <replaceable class="PARAMETER">start</replaceable> , ] { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
+ [ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
</synopsis>
where
@@ -702,7 +705,8 @@ SELECT name FROM distributors ORDER BY code;
<synopsis>
<replaceable class="PARAMETER">table_query</replaceable> EXCEPT [ ALL ] <replaceable class="PARAMETER">table_query</replaceable>
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
- [ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } [ { OFFSET | , } <replaceable class="PARAMETER">start</replaceable> ]]
+ [ LIMIT [ <replaceable class="PARAMETER">start</replaceable> , ] { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
+ [ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
</synopsis>
where
@@ -738,7 +742,7 @@ SELECT name FROM distributors ORDER BY code;
</title>
<para>
<synopsis>
- LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } [ { OFFSET | , } <replaceable class="PARAMETER">start</replaceable> ]
+ LIMIT [ <replaceable class="PARAMETER">start</replaceable> , ] { <replaceable class="PARAMETER">count</replaceable> | ALL }
OFFSET <replaceable class="PARAMETER">start</replaceable>
</synopsis>
@@ -761,14 +765,14 @@ SELECT name FROM distributors ORDER BY code;
constrains the result rows into a unique order. Otherwise you will get
an unpredictable subset of the query's rows---you may be asking for
the tenth through twentieth rows, but tenth through twentieth in what
- ordering? You don't know what ordering, unless you specified ORDER BY.
+ ordering? You don't know what ordering unless you specify ORDER BY.
</para>
<para>
As of <productname>Postgres</productname> 7.0, the
query optimizer takes LIMIT into account when generating a query plan,
so you are very likely to get different plans (yielding different row
- orders) depending on what you give for LIMIT and OFFSET. Thus, using
+ orders) depending on what you use for LIMIT and OFFSET. Thus, using
different LIMIT/OFFSET values to select different subsets of a query
result <emphasis>will give inconsistent results</emphasis> unless
you enforce a predictable result ordering with ORDER BY. This is not
diff --git a/doc/src/sgml/sql.sgml b/doc/src/sgml/sql.sgml
index d0eef867abf..223aee1bc69 100644
--- a/doc/src/sgml/sql.sgml
+++ b/doc/src/sgml/sql.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.21 2001/05/22 16:00:00 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/sql.sgml,v 1.22 2001/09/23 03:39:01 momjian Exp $
-->
<chapter id="sql">
@@ -864,7 +864,8 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replac
[ { UNION | INTERSECT | EXCEPT [ ALL ] } <replaceable class="PARAMETER">select</replaceable> ]
[ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
[ FOR UPDATE [ OF <replaceable class="PARAMETER">class_name</replaceable> [, ...] ] ]
- [ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } [ { OFFSET | , } <replaceable class="PARAMETER">start</replaceable> ]]
+ [ LIMIT [ <replaceable class="PARAMETER">start</replaceable> , ] { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
+ [ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
</synopsis>
</para>
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 24407902bd3..64d71d28bd7 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.252 2001/09/20 14:20:27 petere Exp $
+ * $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.253 2001/09/23 03:39:01 momjian Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -3587,8 +3587,8 @@ OptUseOp: USING all_Op { $$ = $2; }
;
-select_limit: LIMIT select_limit_value ',' select_offset_value
- { $$ = makeList2($4, $2); }
+select_limit: LIMIT select_offset_value ',' select_limit_value
+ { $$ = makeList2($2, $4); }
| LIMIT select_limit_value OFFSET select_offset_value
{ $$ = makeList2($4, $2); }
| LIMIT select_limit_value
--
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