SQL测试空字符串

Question

我有这个查询。 我想要 获取日期范围内的记录 - ＆gt; DONE 获取PriorSurgery ='是'的记录 - ＆gt; DONE 得到顾问不是空白的记录 - 不工作

如何测试无空白。
我试过AND adm.adm_Consultant != ''
我已经AND adm.adm_Consultant <> ''

了

以下一个（看起来更好的方式）

我哪里错了？

SELECT adm.adm_Consultant, adm.adm_PriorSurgery
FROM Admission adm
WHERE  adm.adm_ReferralDate >= '01/01/2014 00:00:00' AND adm.adm_ReferralDate <= '31/12/2014 00:00:00'  
AND adm.adm_PriorSurgery = 'Yes',
AND LENGTH(adm.adm_Consultant) > 0

Answer 1

如果值为null，则

SELECT adm.adm_Consultant, adm.adm_PriorSurgery
FROM Admission adm
WHERE  adm.adm_ReferralDate >= '01/01/2014 00:00:00' AND adm.adm_ReferralDate <= '31/12/2014 00:00:00'  
AND adm.adm_PriorSurgery = 'Yes'
AND adm.adm_Consultant IS NOT NULL