3 files changed, 76 insertions, 0 deletions
diff --git a/mysql-test/main/distinct.result b/mysql-test/main/distinct.result
index 2062ff0091d..0e31a174be7 100644
--- a/mysql-test/main/distinct.result
+++ b/mysql-test/main/distinct.result
@@ -1070,3 +1070,39 @@ UNION
 1
 drop table t1;
 End of 5.5 tests
+#
+# MDEV-27382: OFFSET is ignored when it is combined with the DISTINCT, IN() and JOIN
+#
+CREATE TABLE t1 (
+id int(7) NOT NULL AUTO_INCREMENT,
+name varchar(50) DEFAULT NULL,
+primary key (id)
+);
+INSERT INTO t1 VALUES (1, 'Reed'), (10, 'no-child');
+CREATE TABLE t2 (
+id int(11) NOT NULL AUTO_INCREMENT,
+parent_id int(7) NOT NULL,
+name varchar(100) DEFAULT NULL,
+primary key (id),
+key(parent_id)
+);
+INSERT INTO t2 VALUES (1, 1,'John'), (2, 2,'no-parent');
+SELECT DISTINCT p.id
+FROM t1 p LEFT JOIN t2 c ON p.id = c.parent_id
+WHERE p.id=1
+LIMIT 0;
+id
+SELECT DISTINCT p.id
+FROM t1 p LEFT JOIN t2 c ON p.id = c.parent_id
+WHERE p.id=1
+LIMIT 0 offset 5;
+id
+# Test the second part of the fix: just check that "LIMIT 0 OFFSET n" is
+# handled in the same way as "LIMIT 0"
+explain select * from t1 limit 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Zero limit
+explain select * from t1 limit 0 offset 10;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Zero limit
+drop table t1, t2;
diff --git a/mysql-test/main/distinct.test b/mysql-test/main/distinct.test
index da12c7273b2..32e189da98a 100644
--- a/mysql-test/main/distinct.test
+++ b/mysql-test/main/distinct.test
@@ -818,3 +818,41 @@ UNION
 drop table t1;
 
 --echo End of 5.5 tests
+
+--echo #
+--echo # MDEV-27382: OFFSET is ignored when it is combined with the DISTINCT, IN() and JOIN
+--echo #
+CREATE TABLE t1 (
+  id int(7) NOT NULL AUTO_INCREMENT,
+  name varchar(50) DEFAULT NULL,
+  primary key (id)
+);
+INSERT INTO t1 VALUES (1, 'Reed'), (10, 'no-child');
+
+CREATE TABLE t2 (
+  id int(11) NOT NULL AUTO_INCREMENT,
+  parent_id int(7) NOT NULL,
+  name varchar(100) DEFAULT NULL,
+  primary key (id),
+  key(parent_id)
+);
+
+INSERT INTO t2 VALUES (1, 1,'John'), (2, 2,'no-parent');
+
+SELECT DISTINCT p.id
+FROM t1 p LEFT JOIN t2 c ON p.id = c.parent_id
+WHERE p.id=1
+LIMIT 0;
+
+SELECT DISTINCT p.id
+FROM t1 p LEFT JOIN t2 c ON p.id = c.parent_id
+WHERE p.id=1
+LIMIT 0 offset 5;
+
+--echo # Test the second part of the fix: just check that "LIMIT 0 OFFSET n" is
+--echo # handled in the same way as "LIMIT 0"
+
+explain select * from t1 limit 0;
+explain select * from t1 limit 0 offset 10;
+
+drop table t1, t2;
diff --git a/sql/sql_limit.h b/sql/sql_limit.h
index a4fcedac14a..19c1ce57e99 100644
--- a/sql/sql_limit.h
+++ b/sql/sql_limit.h
@@ -35,6 +35,8 @@ class Select_limit_counters
 
    void set_limit(ha_rows limit, ha_rows offset)
    {
+      if (limit == 0)
+        offset= 0;
       offset_limit_cnt= offset;
       select_limit_cnt= limit;
       if (select_limit_cnt + offset_limit_cnt >=