MySQL 中文网

好像正常的呀！ 你看我的Explain输出，我用的mysql版本是5.1.31-community-Windows
EXPLAIN SELECT * FROM foo WHERE a IN (NULL, 160000, 160001, 160002)\G
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: foo
type: index
possible_keys: PRIMARY
key: PRIMARY
key_len: 4
ref: NULL
rows: 3
Extra: Using where; Using index
1 row in set (0.00 sec)
******************************* ***************************
+------------------+
| version() |
+------------------+
| 5.1.31-community |
+------------------+