SELECT?*?FROM?cms_user?WHERE?age=NULL;

Empty?set?(0.03?sec)

查詢表中記錄age值為null

mysql>?SELECT?*?FROM?cms_user?WHERE?age<=>NULL;

+----+----------+----------+-------------+------------+----------+-------+------+

|?id?|?username?|?password?|?email???????|?regTime????|?face?????|?proId?|?age??|

+----+----------+----------+-------------+------------+----------+-------+------+

|?12?|?test1????|?test1????|sui@qq.com?|?1419811708?|?user.jpg?|?????1?|?NULL?|

+----+----------+----------+-------------+------------+----------+-------+------+

1?row?in?set?(0.03?sec)

查詢表中的 null 值使用 <=>

使用: is null 和 is not null

ELECT?*?FROM?cms_user?WHERE?age?IS?NULL;

+----+----------+----------+-------------+------------+----------+-------+------+

|?id?|?username?|?password?|?email???????|?regTime????|?face?????|?proId?|?age??|

+----+----------+----------+-------------+------------+----------+-------+------+

|?12?|?test1????|?test1????|?user@qq.com?|?1419811708?|?user.jpg?|?????1?|?NULL?|

+----+----------+----------+-------------+------------+----------+-------+------+

1?row?in?set?(0.00?sec)

IS?NOT?NULL

mysql>?SELECT?*?FROM?cms_user?WHERE?age?IS?NOT?NULL;

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