检查列表为空或则空检查SQL

Question

我有这样的查询，

with t as (
     <your query here> 
    ) 
select t.id, t.name, t.randomid, trand.name as randomname 
from t left join 
    t trand 
    on t.randomid = trand.id 
where t.id in (select item from dbo.ufnSplit(@ids,',')); 

Here is code for ufnSplit

如何添加检查，这样如果@ids为空或空才使用where条件，只有在@ids不为null或空时，我才需要这个条件？

where t.id in (select item from dbo.ufnSplit(@ids,',')); 

Answer 1

这将检查@ids是否为空或空，然后检查where子句。

with t as (
     <your query here> 
    ) 
select t.id, t.name, t.randomid, trand.name as randomname 
from t left join 
    t trand 
    on t.randomid = trand.id 
where @ids = '' 
    or @ids is null 
    or t.id in (select item from dbo.ufnSplit(@ids,',')) 

Answer 2

试试这个Where条款

where t.id in (select item from dbo.ufnSplit(@ids,',')) or nullif(@ids,'') is null; 

Answer 3

你可以只使用条件WHERE条款，像这样：

with t as (
     <your query here> 
    ) 
select t.id, t.name, t.randomid, trand.name as randomname 
from t left join 
    t trand 
    on t.randomid = trand.id 
where @ids IS NULL OR t.id IN (select item from dbo.ufnSplit(@ids,',')); 

所以，如果它是NULL它将返回的一切，否则会评估OR条款WHERE的一部分。

您可能需要编辑函数：dbo.ufnSplit才能正常处理NULL输入以使其正常工作。