mysql> desc t1;
+-------+------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+------------+------+-----+---------+-------+
| a | bit(1) | YES | | NULL | |
| b | tinyint(4) | YES | | NULL | |
| c | binary(1) | YES | | NULL | | #binary預設顯示寬度為1
+-------+------------+------+-----+---------+-------+
3 rows in set (0.00 sec)
mysql> alter table t1 modify c binary(30);#修改顯示寬度為30
Query OK, 5 rows affected (0.04 sec)
Records: 5 Duplicates: 0 Warnings: 0
mysql> select * from t1;#查詢發現修改binary顯示寬度前的列還是僅顯示第一個字母,也就是顯示寬度為1
+------+------+--------------------------------+
| a | b | c |
+------+------+--------------------------------+
| | -127 | NULL |
| | 127 | NULL |
| | 28 | NULL |
| | 18 | NULL |
| | 10 | m |
+------+------+--------------------------------+
5 rows in set (0.00 sec)
mysql> insert into t1 values(0,25,'mama haha');#再次插入資料
Query OK, 1 row affected (0.00 sec)
mysql> select * from t1;
+------+------+--------------------------------+
| a | b | c |
+------+------+--------------------------------+
| | -127 | NULL |
| | 127 | NULL |
| | 28 | NULL |
| | 18 | NULL |
| | 10 | m |
| | 25 | mama haha | #再次插入新行,全部binary列值顯示出來
+------+------+--------------------------------+
6 rows in set (0.00 sec)
mysql> insert into t1 values(0,18,'the best one is you');
Query OK, 1 row affected (0.00 sec)
mysql> select * from t1;
+------+------+--------------------------------+
| a | b | c |
+------+------+--------------------------------+
| | -127 | NULL |
| | 127 | NULL |
| | 28 | NULL |
| | 18 | NULL |
| | 10 | m |
| | 25 | mama haha |
| | 18 | the best one is you |
+------+------+--------------------------------+
7 rows in set (0.01 sec)