MySQL 中 不等于 会过滤掉 Null 的问题

SELECT * FROM A WHERE IFNULL(B1,'') != 1

 

测试代码

过滤 type不等于door_open_log_sync，janitor-synchron-status，janitor-synchron，janitor-users-sync

SELECT

    *

FROM

    base_sys_log_api

WHERE

    1 = 1

AND IFNULL(type,'')  != 'door_open_log_sync'

AND IFNULL(type,'')  != 'janitor-synchron-status'

AND IFNULL(type,'')  != 'janitor-synchron'

AND IFNULL(type,'') != 'janitor-users-sync'

ORDER BY

    `id` DESC

LIMIT 0,

50