Commit 49af76ac authored by evgen@moonbone.local's avatar evgen@moonbone.local
Browse files

Bug#31095: Unexpected NULL constant caused server crash. 

The Item_func_rollup_const class is used for wrapping constants to avoid
wrong result for ROLLUP queries with DISTINCT and a constant in the select
list. This class is also used to wrap up a NULL constant but its null_value
wasn't set accordingly. This led to a server crash.

Now the null_value of an object of the Item_func_rollup_const class is set
by its fix_length_and_dec member function.
parent 2a26db1f

mysql-test/r/olap.result

+11 −0
Original line number Diff line number Diff line
@@ -715,3 +715,14 @@ a SUM(a) 
4	4

NULL	14

DROP TABLE t1;

#

# Bug#31095: Unexpected NULL constant caused server crash.

#

create table t1(a int);

insert into t1 values (1),(2),(3);

select count(a) from t1 group by null with rollup;

count(a)

3

3

drop table t1;

##############################################################

mysql-test/t/olap.test

+9 −0
Original line number Diff line number Diff line
@@ -358,3 +358,12 @@ SELECT * FROM (SELECT a, SUM(a) FROM t1 GROUP BY a WITH ROLLUP) as t; 


DROP TABLE t1;



--echo #

--echo # Bug#31095: Unexpected NULL constant caused server crash.

--echo #

create table t1(a int);

insert into t1 values (1),(2),(3);

select count(a) from t1 group by null with rollup;

drop table t1;

--echo ##############################################################

sql/item_func.h

+2 −0
Original line number Diff line number Diff line
@@ -749,6 +749,8 @@ class Item_func_rollup_const :public Item_func 
    collation= args[0]->collation;

    max_length= args[0]->max_length;

    decimals=args[0]->decimals; 

    /* The item could be a NULL constant. */

    null_value= args[0]->null_value;

  }

};