mysql> SELECT 10050001 NOT IN (
-> SELECT `CampusID`
-> FROM `USERS`
-> );
+----------------------------------------------------+
| 10050001 NOT IN (
SELECT `CampusID`
FROM `USERS`
) |
+----------------------------------------------------+
| NULL |
+----------------------------------------------------+
为什么会出现这样的结果呢?
-> SELECT `CampusID`
-> FROM `USERS`
-> );
+----------------------------------------------------+
| 10050001 NOT IN (
SELECT `CampusID`
FROM `USERS`
) |
+----------------------------------------------------+
| NULL |
+----------------------------------------------------+
为什么会出现这样的结果呢?
USERS.CampusID的值是int(11)
我的结果很正确mysql> select 122332 not in (
-> select `aa`
-> from `a`
-> );
+----------------------------------------+
| 122332 not in (
select `aa`
from `a`
) |
+----------------------------------------+
| 1 |
+----------------------------------------+
1 row in set (0.00 sec)
顺便说说,mysql里int(4)和int(11)的最大值都是21亿多的那个,不会因为你改大了它就大的,小心以后溢出了,想大就用big int,或者干脆用varchar等字符型