SQL和不取，或不给予正确的结果

Question

在简单MS SQL查询IAM无法得到结果

SELECT * FROM tblActivityTracker 
WHERE (WoM IN (NULL, 2)) 
AND (DateName = DATENAME(weekday, GETDATE())) 

PLS建议

Answer 1

你不能IN子句中使用null。

查询

SELECT * FROM tblActivityTracker 
WHERE (WoM IN (2) OR Wom is null) -- or Wom = 2 instead of using IN 
AND (DateName = DATENAME(weekday, GETDATE())); 

Answer 2

试试这个

SELECT * FROM tblActivityTracker 
WHERE (WoM =2 OR Wom IS NULL) 
AND (DateName = DATENAME(weekday, GETDATE())); 

或者试试这个

SELECT * FROM tblActivityTracker 
WHERE (WoM in('NULL','2')) 
AND (DateName = DATENAME(weekday, GETDATE())); 

Answer 3

你能做的最好的是使用ISNULL

SELECT * FROM tblActivityTracker 
WHERE isnull(WoM,'') IN ('', '2') 
AND DateName = DATENAME(weekday, GETDATE()) 

个

Answer 4

感谢的建议...... 其实下面的查询帮助

SELECT * FROM tblActivityTracker 
WHERE (WoM IN (2)) AND (DATENAME(weekday, GETDATE()) = DateName) OR 
    (WoM IS NULL) AND (DATENAME(weekday, GETDATE()) = DateName)