Upozornění:#1265 Data zkrácena pro sloupec 'pdd' na řádku 1

S největší pravděpodobností tlačíte řetězec 'NULL' k tabulce, spíše než skutečné NULL , ale mohou se dít i jiné věci, příklad:

mysql> CREATE TABLE date_test (pdd DATE NOT NULL);
Query OK, 0 rows affected (0.11 sec)

mysql> INSERT INTO date_test VALUES (NULL);
ERROR 1048 (23000): Column 'pdd' cannot be null
mysql> INSERT INTO date_test VALUES ('NULL');
Query OK, 1 row affected, 1 warning (0.05 sec)

mysql> show warnings;
+---------+------+------------------------------------------+
| Level   | Code | Message                                  |
+---------+------+------------------------------------------+
| Warning | 1265 | Data truncated for column 'pdd' at row 1 |
+---------+------+------------------------------------------+
1 row in set (0.00 sec)

mysql> SELECT * FROM date_test;
+------------+
| pdd        |
+------------+
| 0000-00-00 |
+------------+
1 row in set (0.00 sec)

mysql> ALTER TABLE date_test MODIFY COLUMN pdd DATE NULL;
Query OK, 1 row affected (0.15 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> INSERT INTO date_test VALUES (NULL);
Query OK, 1 row affected (0.06 sec)

mysql> SELECT * FROM date_test;
+------------+
| pdd        |
+------------+
| 0000-00-00 |
| NULL       |
+------------+
2 rows in set (0.00 sec)