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Fixed bug #18925: wrong results for queries with

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subqueries on information schema that use MIN/MAX aggregation.

Execution of some correlated subqueries may set the value
of null_row to 1 for tables used in the subquery.
If the the subquery is on information schema it causes
rejection of any row for the following executions of
the subquery in the case when an optimization filtering
by some condition is applied.

The fix restores the value of the null_row flag for 
each execution of a subquery on information schema.
This commit is contained in:
igor@olga.mysql.com 2006-07-22 12:44:54 -07:00
parent bcf822841b
commit 66ecb7df81
3 changed files with 96 additions and 0 deletions
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62
mysql-test/r/information_schema.result
View file

@ -1170,3 +1170,65 @@ f1()
DROP FUNCTION f1;
DROP PROCEDURE p1;
DROP USER mysql_bug20230@localhost;
SELECT t.table_name, c1.column_name
FROM information_schema.tables t
INNER JOIN
information_schema.columns c1
ON t.table_schema = c1.table_schema AND
t.table_name = c1.table_name
WHERE t.table_schema = 'information_schema' AND
c1.ordinal_position =
( SELECT COALESCE(MIN(c2.ordinal_position),1)
FROM information_schema.columns c2
WHERE c2.table_schema = t.table_schema AND
c2.table_name = t.table_name AND
c2.column_name LIKE '%SCHEMA%'
);
table_name column_name
CHARACTER_SETS CHARACTER_SET_NAME
COLLATIONS COLLATION_NAME
COLLATION_CHARACTER_SET_APPLICABILITY COLLATION_NAME
COLUMNS TABLE_SCHEMA
COLUMN_PRIVILEGES TABLE_SCHEMA
KEY_COLUMN_USAGE CONSTRAINT_SCHEMA
ROUTINES ROUTINE_SCHEMA
SCHEMATA SCHEMA_NAME
SCHEMA_PRIVILEGES TABLE_SCHEMA
STATISTICS TABLE_SCHEMA
TABLES TABLE_SCHEMA
TABLE_CONSTRAINTS CONSTRAINT_SCHEMA
TABLE_PRIVILEGES TABLE_SCHEMA
TRIGGERS TRIGGER_SCHEMA
USER_PRIVILEGES GRANTEE
VIEWS TABLE_SCHEMA
SELECT t.table_name, c1.column_name
FROM information_schema.tables t
INNER JOIN
information_schema.columns c1
ON t.table_schema = c1.table_schema AND
t.table_name = c1.table_name
WHERE t.table_schema = 'information_schema' AND
c1.ordinal_position =
( SELECT COALESCE(MIN(c2.ordinal_position),1)
FROM information_schema.columns c2
WHERE c2.table_schema = 'information_schema' AND
c2.table_name = t.table_name AND
c2.column_name LIKE '%SCHEMA%'
);
table_name column_name
CHARACTER_SETS CHARACTER_SET_NAME
COLLATIONS COLLATION_NAME
COLLATION_CHARACTER_SET_APPLICABILITY COLLATION_NAME
COLUMNS TABLE_SCHEMA
COLUMN_PRIVILEGES TABLE_SCHEMA
KEY_COLUMN_USAGE CONSTRAINT_SCHEMA
ROUTINES ROUTINE_SCHEMA
SCHEMATA SCHEMA_NAME
SCHEMA_PRIVILEGES TABLE_SCHEMA
STATISTICS TABLE_SCHEMA
TABLES TABLE_SCHEMA
TABLE_CONSTRAINTS CONSTRAINT_SCHEMA
TABLE_PRIVILEGES TABLE_SCHEMA
TRIGGERS TRIGGER_SCHEMA
USER_PRIVILEGES GRANTEE
VIEWS TABLE_SCHEMA

33
mysql-test/t/information_schema.test
View file

@ -887,4 +887,37 @@ DROP FUNCTION f1;
DROP PROCEDURE p1;
DROP USER mysql_bug20230@localhost;
#
# Bug#18925: subqueries with MIN/MAX functions on INFORMARTION_SCHEMA
#
SELECT t.table_name, c1.column_name
FROM information_schema.tables t
INNER JOIN
information_schema.columns c1
ON t.table_schema = c1.table_schema AND
t.table_name = c1.table_name
WHERE t.table_schema = 'information_schema' AND
c1.ordinal_position =
( SELECT COALESCE(MIN(c2.ordinal_position),1)
FROM information_schema.columns c2
WHERE c2.table_schema = t.table_schema AND
c2.table_name = t.table_name AND
c2.column_name LIKE '%SCHEMA%'
);
SELECT t.table_name, c1.column_name
FROM information_schema.tables t
INNER JOIN
information_schema.columns c1
ON t.table_schema = c1.table_schema AND
t.table_name = c1.table_name
WHERE t.table_schema = 'information_schema' AND
c1.ordinal_position =
( SELECT COALESCE(MIN(c2.ordinal_position),1)
FROM information_schema.columns c2
WHERE c2.table_schema = 'information_schema' AND
c2.table_name = t.table_name AND
c2.column_name LIKE '%SCHEMA%'
);
# End of 5.0 tests.

1
sql/sql_show.cc
View file

@ -3963,6 +3963,7 @@ bool get_schema_tables_result(JOIN *join)
table_list->table->file->delete_all_rows();
free_io_cache(table_list->table);
filesort_free_buffers(table_list->table);
table_list->table->null_row= 0;
}
else
table_list->table->file->records= 0;