《MYSQL教程mysql int(1) 與 tinyint(1) 區(qū)別》要點(diǎn):
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問題:
mysql int(1) tinyint(1)有什么區(qū)別?
我指定了字段長度,類型還有意義嗎?
?
Reply:
mysql 中int(1)和tinyint(1)中的1只是指定顯示長度,并不表示存儲(chǔ)長度,只有字段指定zerofill是有用
如int(3),如果實(shí)際值是2,如果列指定了zerofill,查詢結(jié)果便是002,左邊用0來填充.
?
TINYINT[(M)] [UNSIGNED] [ZEROFILL]?MYSQL應(yīng)用
A very small integer. The signed range is -128 to 127. The unsigned range is 0 to 255.?MYSQL利用
INT[(M)] [UNSIGNED] [ZEROFILL]?MYSQL利用
A normal-size integer. The signed range is -2147483648 to 2147483647. The unsigned range is 0 to 4294967295.?
位數(shù)限制根本沒有意義.
?MYSQL應(yīng)用
mysql> create table testint(id int(1), col2 tinyint(1));
Query OK, 0 rows affected (0.06 sec)MYSQL利用
mysql> insert into testint values(256, 257);
Query OK, 1 row affected, 1 warning (0.03 sec)MYSQL利用
mysql> select * from testint;
+------+------+
| id | col2 |
+------+------+
| 256 | 127 |
+------+------+
1 row in set (0.02 sec)MYSQL利用
mysql> insert into testint values(336, 257);
Query OK, 1 row affected, 1 warning (0.02 sec)MYSQL利用
mysql> select * from testint;
+------+------+
| id | col2 |
+------+------+
| 256 | 127 |
| 336 | 127 |
+------+------+
2 rows in set (0.00 sec)MYSQL利用
mysql> insert into testint values(336, 255);
Query OK, 1 row affected, 1 warning (0.03 sec)MYSQL利用
mysql> select * from testint;
+------+------+
| id | col2 |
+------+------+
| 256 | 127 |
| 336 | 127 |
| 336 | 127 |
+------+------+
3 rows in set (0.00 sec)MYSQL利用
mysql>MYSQL利用
上邊的warning提示.
----------------------------
mysql?? 中?? 真,假?? 這樣的數(shù)據(jù)應(yīng)該用什么數(shù)據(jù)類型?
reply:tinyint(1)MYSQL利用
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