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Fixed LP bug #791761.

Browse source 
An aggregating query over an empty set of a join of two tables
with a rejecting HAVING clause erroneously could return a row.
It could happen in the cases when the optimizer made a conclusion
that the aggregating set was empty.
Wrong results were produced because the server missed initial
setting for aggregation functions in the mentioned cases.
This commit is contained in:
Igor Babaev 2011-07-20 21:55:55 -07:00
parent 6dc1cdc205
commit 2e8542f462
5 changed files with 54 additions and 1 deletions
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24
mysql-test/r/having.result
View file

@ -570,3 +570,27 @@ ORDER BY t1.f1;
f1
DROP TABLE t1,t2;
End of 5.1 tests
#
# LP bug #791761: MAX over an empty join + HAVING
#
CREATE TABLE t1 (a int, b int , KEY (b)) ;
INSERT INTO t1 VALUES (3,1);
CREATE TABLE t2 (a int NOT NULL ) ;
INSERT INTO t2 VALUES (29);
SELECT MAX(t1.b) FROM t1,t2 WHERE t2.a > 0 HAVING MAX(t1.b) <> 6;
MAX(t1.b)
1
SELECT MAX(t1.b) FROM t1,t2 WHERE t2.a > 0 HAVING MAX(t1.b) IS NULL;
MAX(t1.b)
EXPLAIN
SELECT MAX(t1.b) FROM t1,t2 WHERE t2.a < 0 HAVING MAX(t1.b) <> 6;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
SELECT MAX(t1.b) FROM t1,t2 WHERE t2.a < 0 HAVING MAX(t1.b) <> 6;
MAX(t1.b)
CREATE TABLE t3 ( f3 int) ;
INSERT INTO t3 VALUES (NULL);
SELECT MAX(t1.b) AS f FROM t1 JOIN t2 ON t2.a != 0
WHERE (SELECT f3 FROM t3) <> 0 HAVING f <> 6 ;
f
DROP TABLE t1,t2,t3;

25
mysql-test/t/having.test
View file

@ -591,3 +591,28 @@ DROP TABLE t1,t2;
--echo End of 5.1 tests
--echo #
--echo # LP bug #791761: MAX over an empty join + HAVING
--echo #
CREATE TABLE t1 (a int, b int , KEY (b)) ;
INSERT INTO t1 VALUES (3,1);
CREATE TABLE t2 (a int NOT NULL ) ;
INSERT INTO t2 VALUES (29);
SELECT MAX(t1.b) FROM t1,t2 WHERE t2.a > 0 HAVING MAX(t1.b) <> 6;
SELECT MAX(t1.b) FROM t1,t2 WHERE t2.a > 0 HAVING MAX(t1.b) IS NULL;
EXPLAIN
SELECT MAX(t1.b) FROM t1,t2 WHERE t2.a < 0 HAVING MAX(t1.b) <> 6;
SELECT MAX(t1.b) FROM t1,t2 WHERE t2.a < 0 HAVING MAX(t1.b) <> 6;
CREATE TABLE t3 ( f3 int) ;
INSERT INTO t3 VALUES (NULL);
SELECT MAX(t1.b) AS f FROM t1 JOIN t2 ON t2.a != 0
WHERE (SELECT f3 FROM t3) <> 0 HAVING f <> 6 ;
DROP TABLE t1,t2,t3;

1
sql/item.h
View file

@ -1020,6 +1020,7 @@ public:
virtual bool set_fake_select_as_master_processor(uchar *arg) { return 0; }
virtual bool view_used_tables_processor(uchar *arg) { return 0; }
virtual bool eval_not_null_tables(uchar *opt_arg) { return 0; }
virtual bool clear_sum_processor(uchar *opt_arg) { return 0; }
/* To call bool function for all arguments */
struct bool_func_call_args

1
sql/item_sum.h
View file

@ -388,6 +388,7 @@ public:
{
return trace_unsupported_by_check_vcol_func_processor(func_name());
}
bool clear_sum_processor(uchar *arg) { clear(); return 0; }
};

4
sql/sql_select.cc
View file

@ -10146,7 +10146,9 @@ return_zero_rows(JOIN *join, select_result *result, List<TABLE_LIST> &tables,
TABLE_LIST *table;
while ((table= ti++))
mark_as_null_row(table->table); // All fields are NULL
if (having && having->val_int() == 0)
if (having &&
!having->walk(&Item::clear_sum_processor, FALSE, NULL) &&
having->val_int() == 0)
send_row=0;
}
if (!(result->send_fields(fields,