Fixed bug #20519.

The bug was due to a loss happened during a refactoring made
on May 30 2005 that modified the function JOIN::reinit.
As a result of it for any subquery the value of offset_limit_cnt
was not restored for the following executions. Yet the first 
execution of the subquery made it equal to 0.
The fix restores this value in the function JOIN::reinit.  

1 files changed, 40 insertions, 0 deletions

diff --git a/mysql-test/t/subselect.test b/mysql-test/t/subselect.test
index 9fc4f8a8d4e..310adcc5323 100644
--- a/mysql-test/t/subselect.test
+++ b/mysql-test/t/subselect.test
@@ -2161,3 +2161,43 @@ SELECT t1.i FROM t1 WHERE t1.i = CAST((SELECT MAX(i) FROM t2) AS UNSIGNED);
 
 DROP TABLE t1;
 DROP TABLE t2;
+
+# 
+# Bug#20519: subselect with LIMIT M, N
+#
+
+CREATE TABLE t1 (
+  id bigint(20) unsigned NOT NULL auto_increment,
+  name varchar(255) NOT NULL,
+  PRIMARY KEY  (id)
+);
+INSERT INTO t1 VALUES
+  (1, 'Balazs'), (2, 'Joe'), (3, 'Frank');
+
+CREATE TABLE t2 (
+  id bigint(20) unsigned NOT NULL auto_increment,
+  mid bigint(20) unsigned NOT NULL,
+  date date NOT NULL,
+  PRIMARY KEY  (id)
+);
+INSERT INTO t2 VALUES 
+  (1, 1, '2006-03-30'), (2, 2, '2006-04-06'), (3, 3, '2006-04-13'),
+  (4, 2, '2006-04-20'), (5, 1, '2006-05-01');
+
+SELECT *,
+      (SELECT date FROM t2 WHERE mid = t1.id
+         ORDER BY date DESC LIMIT 0, 1) AS date_last,
+      (SELECT date FROM t2 WHERE mid = t1.id
+         ORDER BY date DESC LIMIT 3, 1) AS date_next_to_last
+  FROM t1;
+SELECT *,
+      (SELECT COUNT(*) FROM t2 WHERE mid = t1.id
+         ORDER BY date DESC LIMIT 1, 1) AS date_count
+  FROM t1;
+SELECT *,
+      (SELECT date FROM t2 WHERE mid = t1.id
+         ORDER BY date DESC LIMIT 0, 1) AS date_last,
+      (SELECT date FROM t2 WHERE mid = t1.id
+         ORDER BY date DESC LIMIT 1, 1) AS date_next_to_last
+  FROM t1;
+DROP TABLE t1,t2;