Question

我想检索DaysVisted在两个值之间的行，例如，如果@days是90，则获取DaysVisited在90到60之间的记录，如果@days是60，则获取DaysVisited在60到30之间的记录。

以下查询未给我正确的记录：

declare @days int
set @days = 60
select * from table where
DaysVisited >=
CASE                
   when  (@days = 90) then 
   when  (@days = 60) then @days       
   when  (@days = 0) then 0
END

我想这样：

declare @days int
set @days = 60
select * from table where

CASE                
   when  (@days = 90) then DaysVisited >= 90 and DaysVisited <= 60 
   when  (@days = 60) then DaysVisited >= 60 and DaysVisited <= 30 
   when  (@days = 0) then 0
END

Answer 1

您的逻辑是不可能的，列不能同时低于60且高于90。试试这个：

DECLARE @days int = 60

SELECT * 
FROM 
  yourtable
WHERE
  DaysVisited between 
    case when @days < 30 then 0 else @days-30 end and @days

Answer 2

DECLARE @days int = 60;
DECLARE @MaxDay INT; 
SELECT @MaxDay = MAX(DaysVisited) FROM YourTable;
SELECT *
FROM YourTable
WHERE DaysVisited BETWEEN @days AND 
      CASE 
          WHEN @days=60 THEN 90
          ELSE @MaxDay
       END

sql server multi case where子句

2 个答案: