语句的困惑
SELECT *
FROM ipi
WHERE (ISNULL(subslot, '') = '1') AND (ISNULL(equipmentn, '') LIKE '%%') AND
(ISNULL(clientn, '') LIKE '%%') AND (ISNULL(inttype, '') LIKE '%%') AND (ISNULL(port, '') = '')
最后的 AND (ISNULL(port, '') = '') 去掉就正常
后来发现一句中不能有两个以上的 = '',否则就什么都选不出来。
为什么 ?