Bug #1839 Delete with single row subquery causes lost of connection
Submitted: 14 Nov 2003 10:59 Modified: 17 Nov 2003 2:32
Reporter: Igor Babaev Email Updates:
Status: Closed Impact on me:
Category:MySQL Server Severity:S1 (Critical)
Version:4.1.1 OS:Any (All)
Assigned to: Oleksandr Byelkin CPU Architecture:Any

[14 Nov 2003 10:59] Igor Babaev
If the where condition in a delete statement contains a single row sub-query 
whose result set happens to have more that 1 rows (error 1241) then the 
execution of this statement might cause lost of connection. The failure occurs 
for the sdelete statements with any dependent sub-query returning more than 1 
rows and for the delete statements with dependent subqueries used in any 
predicates except '='. 

How to repeat:
This a slightly modified example from subselect.test: 
create table t11 (a int NOT NULL, b int, primary key (a)); 
create table t12 (a int NOT NULL, b int, primary key (a)); 
create table t2 (a int NOT NULL, b int, primary key (a)); 
insert into t11 values (0, 10),(1, 11),(2, 12); 
insert into t12 values (33, 10),(22, 11),(2, 12); 
insert into t2 values (1, 21),(2, 12),(3, 23); 
select * from t11; 
select * from t12; 
select * from t2; 
delete t11.*, t12.* from t11,t12 where t11.a = t12.a and t11.b > (select b 
from t2); 
select * from t2;
[15 Nov 2003 11:54] Oleksandr Byelkin
  1.1600 03/11/15 21:52:21 bell@sanja.is.com.ua +3 -0 
  fixed error handling inside su_select() for multidelete 
[17 Nov 2003 2:32] Oleksandr Byelkin
Thank you for bugreport. Patch for this bug is pushed in source repository