Question

我做这样的事情很好：

select nameOfCols 
from 
FACost
inner join  FAT as D  on d.nid=a.atypeid  
and
d.nid in (select item from SplitString('1,2,3,',','))

但是，当我使用案例来处理用户动态进入的情况时，可以进入＆＃39;＆＃39;而不是＆＃39; 1,2,3，＆＃39;。然后它在我的案例条件中给出了错误

declare @selectedAssetTypeID varchar(50)='1,2,3,'
select nameOfCols 
from 
FACost
inner join  FAT as D  on d.nid=a.atypeid  
and
case when @selectedAssetTypeID<>'' then  d.nid in (select item from SplitString( @selectedAssetTypeID,',')) else d.nid=1 end     //error causing lines

错误是：

Msg 156, Level 15, State 1, Line 33
Incorrect syntax near the keyword 'in'.
Msg 156, Level 15, State 1, Line 33
Incorrect syntax near the keyword 'else'.

Answer 1

使用and和or条件而不是case表达式。您拥有的case表达式是指定值（else d.nid=1）或检查真/假条件（d.nid in (select item from SplitString( @selectedAssetTypeID,','))）。

and (
(@selectedAssetTypeID <>'' and  d.nid in (select item from SplitString( @selectedAssetTypeID,',')) )
or (d.nid=1) 
)

Answer 2

您不能将in子句与case语句一起使用。因为Case必须为每个语句返回一个值（true或false）

您可以将查询拆分为两个区块，也可以使用＆＃34; OR＆＃34;子句。

IF @selectedAssetTypeID = " "
BEGIN
     select nameOfCols 
     from FACost 
     inner join FAT as D  
      on (d.nid = a.atypeid)
     where d.nid = 1
END
ELSE
BEGIN
     select nameOfCols 
     from FACost 
     inner join FAT as D  
      on (d.nid = a.atypeid)
     where d.nid IN
     (select item from SplitString( @selectedAssetTypeID,','))
 END

您还可以使用＆＃34; OR＆＃34;条款

select nameOfCols 
     from FACost 
     inner join FAT as D  
      on (d.nid = a.atypeid)
     where ((@selectedAssetTypeID <>'' and  d.nid in (select item from SplitString(@selectedAssetTypeID,',')))
or (d.nid=1))

关于类似问题的讨论的链接如下

https://social.msdn.microsoft.com/Forums/sqlserver/en-US/bc8a7a0b-1980-4481-a2df-6a5fde38f362/in-clause-in-case-statement?forum=sqlgetstarted

为什么sql案例条件给出错误

2 个答案: