一个Case When条件语句求解解决思路

一个Case When条件语句求解
表A,表B

SQL code


Select * From 表A Where .....

SQL code


Select ItemName From 表B Where plan_id=@plan_id

作为条件,它的结果有二种可能,一种是ItemName = 'xx' ,那么就直接执行

SQL code


Select * From 表A

另一种可能就是它可能数字或是记录有多条,那么就执行

SQL code


Select * From 表A Where ID IN (Select ItemName From 表B Where plan_id=@plan_id )

不知有没有描述清楚

------解决方案--------------------

SQL code


Select ItemName From 表B Where plan_id=@plan_id
if (@@rowcount = 1) and (ItemName   =   'xx')
    Select * From 表A
else
    Select * From 表A Where ID IN (Select ItemName From 表B Where plan_id=@plan_id )

------解决方案--------------------

SQL code

drop table tb
create table tb (id int,AN varchar(8000),CN varchar(8000))
insert tb select 1,'a','121'
insert tb select 2,'','123'
insert tb select 3,'s','123'

create table tb (id int,AN varchar(8000),CN varchar(8000))
insert tb select 1,'a','121'
insert tb select 2,'','123'
if(exists(select 1 from tb where an != '' and cn='123') ) 
exec('select * from tb where an !='''' and cn =''123''')
else
exec('select * from tb where an ='''' and cn =''123''')

------解决方案--------------------
使用
if else

SQL code


declare @ID int
set @ID = 1
if @ID = 1
begin
select COunt(*) from  sysobjects
set @ID = 2
end
else
select count(*) from sysfiles

------解决方案--------------------
if @@rowcount = 1 and Case_ItemID = 'All'
????????????????////////
郁闷，怎么能这样用的
----------------

SQL code


declare @DisplayChar int
declare @Plan_ID int
declare @Case_ItemID varchar(20)
set @Plan_ID  ='1006'
Select @Case_ItemID = Ltrim(Case_ItemID) 
From Report_Planparameter2 
      Where Plan_Id =@Plan_ID  and Case_name = 'account'
if @@rowcount = 1 and @Case_ItemID = 'All'
   select @DisplayChar = ''
else
   select @DisplayChar = '1'

一个Case When条件语句求解解决思路

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