Details
-
Bug
-
Status: Closed (View Workflow)
-
Major
-
Resolution: Fixed
-
5.5, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5
-
None
Description
ALTER
After a meangless alter from PONT to LINESTRING, a SELECT query still returns POINT values.
CREATE OR REPLACE TABLE t1 (a POINT) ENGINE=MyISAM; |
INSERT INTO t1 VALUES (Point(0,0)); |
ALTER TABLE t1 MODIFY a LINESTRING; |
SHOW CREATE TABLE t1; |
+-------+------------------------------------------------------------------------------------------+
|
| Table | Create Table |
|
+-------+------------------------------------------------------------------------------------------+
|
| t1 | CREATE TABLE `t1` (
|
`a` linestring DEFAULT NULL
|
) ENGINE=MyISAM DEFAULT CHARSET=latin1 |
|
+-------+------------------------------------------------------------------------------------------+
|
Notice, it altered the table without any warnings, although the two data types are not really incompatible.
Now if I do a query, it still return points from a column of the LINESTRING data type:
SELECT AsText(a) FROM t1; |
+------------+
|
| AsText(a) |
|
+------------+
|
| POINT(0 0) |
|
+------------+
|
Note, inserting a POINT value to a LINESTRING column correctly returns an error:
INSERT INTo t1 VALUES (Point(0,0)); |
ERROR 1366 (22007): Incorrect LINESTRING value: 'POINT' for column `test`.`t1`.`a` at row 1
|
INSERT..SELECT
The same problem is repeatable in INSERT..SELECT:
CREATE OR REPLACE TABLE t1 (a LINESTRING); |
CREATE OR REPLACE TABLE t2 (a POINT); |
INSERT INTO t2 VALUES (POINT(0,0)); |
INSERT INTO t1 SELECT * FROM t2; |
SELECT AsText(a) FROM t1; |
+------------+
|
| AsText(a) |
|
+------------+
|
| POINT(0 0) |
|
+------------+
|
Notice, t1.a is LINESTRING, but it stores POINT values.