drop table if exists t1, t2, t3; create table t1 (kill_id int); insert into t1 values(connection_id()); select ((@id := kill_id) - kill_id) from t1; ((@id := kill_id) - kill_id) 0 kill @id; select ((@id := kill_id) - kill_id) from t1; ((@id := kill_id) - kill_id) 0 select @id != connection_id(); @id != connection_id() 1 select 4; 4 4 drop table t1; kill (select count(*) from mysql.user); ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'select count(*) from mysql.user)' at line 1 create table t1 (id int primary key); create table t2 (id int unsigned not null); insert into t2 select id from t1; create table t3 (kill_id int); insert into t3 values(connection_id()); select id from t1 where id in (select distinct id from t2); select ((@id := kill_id) - kill_id) from t3; ((@id := kill_id) - kill_id) 0 kill @id; Got one of the listed errors drop table t1, t2, t3; select get_lock("a", 10); get_lock("a", 10) 1 select get_lock("a", 10); get_lock("a", 10) NULL select 1; 1 1 select RELEASE_LOCK("a"); RELEASE_LOCK("a") 1 create table t1(f1 int); create function bug27563() returns int(11) deterministic begin declare continue handler for sqlstate '70100' set @a:= 'killed'; declare continue handler for sqlexception set @a:= 'exception'; set @a= get_lock("lock27563", 10); return 1; end| select get_lock("lock27563",10); get_lock("lock27563",10) 1 insert into t1 values (bug27563()); ERROR 70100: Query execution was interrupted select @a; @a NULL select * from t1; f1 insert into t1 values(0); update t1 set f1= bug27563(); ERROR 70100: Query execution was interrupted select @a; @a NULL select * from t1; f1 0 insert into t1 values(1); delete from t1 where bug27563() is null; ERROR 70100: Query execution was interrupted select @a; @a NULL select * from t1; f1 0 1 select * from t1 where f1= bug27563(); ERROR 70100: Query execution was interrupted select @a; @a NULL create procedure proc27563() begin declare continue handler for sqlstate '70100' set @a:= 'killed'; declare continue handler for sqlexception set @a:= 'exception'; select get_lock("lock27563",10); select "shouldn't be selected"; end| call proc27563(); get_lock("lock27563",10) NULL ERROR 70100: Query execution was interrupted select @a; @a NULL create table t2 (f2 int); create trigger trg27563 before insert on t1 for each row begin declare continue handler for sqlstate '70100' set @a:= 'killed'; declare continue handler for sqlexception set @a:= 'exception'; set @a:= get_lock("lock27563",10); insert into t2 values(1); end| insert into t1 values(2),(3); ERROR 70100: Query execution was interrupted select @a; @a NULL select * from t1; f1 0 1 select * from t2; f2 select release_lock("lock27563"); release_lock("lock27563") 1 drop table t1, t2; drop function bug27563; drop procedure proc27563;