From e5e1ea602d9393a29400098dc40d0f9de846fdd1 Mon Sep 17 00:00:00 2001
From: Adrian Holovaty <adrian@holovaty.com>
Date: Fri, 19 Aug 2005 21:51:14 +0000
Subject: [PATCH] Fixed #350 -- 'offset' DB API parameter now works in MySQL 3.
 Tests from [540] pass. Thanks, ronan@cremin.com

git-svn-id: http://code.djangoproject.com/svn/django/trunk@541 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/core/db/__init__.py            | 1 +
 django/core/db/backends/mysql.py      | 6 ++++++
 django/core/db/backends/postgresql.py | 6 ++++++
 django/core/db/backends/sqlite3.py    | 6 ++++++
 django/core/meta/__init__.py          | 5 ++---
 5 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/django/core/db/__init__.py b/django/core/db/__init__.py
index 43ca2b26196..d59f44bce3e 100644
--- a/django/core/db/__init__.py
+++ b/django/core/db/__init__.py
@@ -37,6 +37,7 @@ dictfetchall = dbmod.dictfetchall
 get_last_insert_id = dbmod.get_last_insert_id
 get_date_extract_sql = dbmod.get_date_extract_sql
 get_date_trunc_sql = dbmod.get_date_trunc_sql
+get_limit_offset_sql = dbmod.get_limit_offset_sql
 get_table_list = dbmod.get_table_list
 get_relations = dbmod.get_relations
 OPERATOR_MAPPING = dbmod.OPERATOR_MAPPING
diff --git a/django/core/db/backends/mysql.py b/django/core/db/backends/mysql.py
index 4a54a277e41..f65398b3b60 100644
--- a/django/core/db/backends/mysql.py
+++ b/django/core/db/backends/mysql.py
@@ -71,6 +71,12 @@ def get_date_trunc_sql(lookup_type, field_name):
         subtractions.append(" - interval (DATE_FORMAT(%s, '%%%%m')-1) month" % field_name)
     return "(%s - %s)" % (field_name, ''.join(subtractions))
 
+def get_limit_offset_sql(limit, offset=None):
+    sql = "LIMIT "
+    if offset and offset != 0:
+        sql += "%s," % offset
+    return sql + str(limit)
+
 def get_table_list(cursor):
     "Returns a list of table names in the current database."
     cursor.execute("SHOW TABLES")
diff --git a/django/core/db/backends/postgresql.py b/django/core/db/backends/postgresql.py
index 94a6ed35c36..0afeec6f30c 100644
--- a/django/core/db/backends/postgresql.py
+++ b/django/core/db/backends/postgresql.py
@@ -71,6 +71,12 @@ def get_date_trunc_sql(lookup_type, field_name):
     # http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
     return "DATE_TRUNC('%s', %s)" % (lookup_type, field_name)
 
+def get_limit_offset_sql(limit, offset=None):
+    sql = "LIMIT %s" % limit
+    if offset and offset != 0:
+        sql += " OFFSET %s" % offset
+    return sql
+
 def get_table_list(cursor):
     "Returns a list of table names in the current database."
     cursor.execute("""
diff --git a/django/core/db/backends/sqlite3.py b/django/core/db/backends/sqlite3.py
index 38ce767dfb1..eef596eff0d 100644
--- a/django/core/db/backends/sqlite3.py
+++ b/django/core/db/backends/sqlite3.py
@@ -97,6 +97,12 @@ def get_date_trunc_sql(lookup_type, field_name):
     # sqlite doesn't support DATE_TRUNC, so we fake it as above.
     return 'django_date_trunc("%s", %s)' % (lookup_type.lower(), field_name)
 
+def get_limit_offset_sql(limit, offset=None):
+    sql = "LIMIT %s" % limit
+    if offset and offset != 0:
+        sql += " OFFSET %s" % offset
+    return sql
+
 def _sqlite_date_trunc(lookup_type, dt):
     try:
         dt = typecasts.typecast_timestamp(dt)
diff --git a/django/core/meta/__init__.py b/django/core/meta/__init__.py
index e50870d9c75..5846fdcc5cc 100644
--- a/django/core/meta/__init__.py
+++ b/django/core/meta/__init__.py
@@ -1277,10 +1277,9 @@ def function_get_sql_clause(opts, **kwargs):
 
     # LIMIT and OFFSET clauses
     if kwargs.get('limit') is not None:
-        limit_sql = " LIMIT %s " % kwargs['limit']
-        if kwargs.get('offset') is not None and kwargs['offset'] != 0:
-            limit_sql += "OFFSET %s " % kwargs['offset']
+        limit_sql = " %s " % db.get_limit_offset_sql(kwargs['limit'], kwargs.get('offset'))
     else:
+        assert kwargs.get('offset') is None, "'offset' is not allowed without 'limit'"
         limit_sql = ""
 
     return select, " FROM " + ",".join(tables) + (where and " WHERE " + " AND ".join(where) or "") + (order_by and " ORDER BY " + order_by or "") + limit_sql, params