Sql query Where clause filter on code number 如何在没有过滤器的情况下获取所有记录？

Question

我想按照我的查询所示明智地获取数据状态，

select  Zipcode,
(CASE pobox
       WHEN 1 THEN 'Available'
       WHEN 2 THEN 'Reserved' 
       WHEN 3 THEN 'Assigned'
       WHEN 4 THEN 'Closed'
END) as ' Status'
from custom_pobox  
where pobox=@Status

假设@status = 0 或 1 或 2 任意值

但是我们在数据库中有从 0 到 4 的值我想显示所有数据如果人 select 全部来自下拉列表

那么我将如何更改此查询？

希望得到您的建议

Answer 1

为了获得所有行，你的 where 子句应该有

where (@status <> 0  AND pobox = @Status) OR (@status = 0 AND 1=1)

然而，第二个 OR 有一些冗余的过滤器，应该只有 @status= 0

where (@status <> 0  AND pobox = @Status) OR (@status = 0)

Answer 2

Pass 'ALL' if person select all from dropdown and write query like below:    
       select  Zipcode, (CASE pobox
       WHEN 1 THEN 'Available'
       WHEN 2 THEN 'Reserved' 
       WHEN 3 THEN 'Assigned'
       WHEN 4 THEN 'Closed'
END) as ' Status'
from custom_pobox  
where CASE WHEN @Status <> 'ALL' THEN pobox=@Status ELSE 1=1 END

Answer 3

SELECT Zipcode, (CASE pobox
   WHEN 1 THEN 'Available'
   WHEN 2 THEN 'Reserved' 
   WHEN 3 THEN 'Assigned'
   WHEN 4 THEN 'Closed'
END) as ' Status'
FROM custom_pobox  
WHERE  Status IN( CASE WHEN @ALL <> 1 THEN (SELCECT CASE pobox
       WHEN 1 THEN 'Available'
       WHEN 2 THEN 'Reserved' 
       WHEN 3 THEN 'Assigned'
       WHEN 4 THEN 'Closed'
END) FROM CUSTOM_POBOX) ELSE @STATUS END)

Sql query Where clause filter on code number 如何在没有过滤器的情况下获取所有记录？

Sql query Where clause filter on code number how to get all record without filter?

sql

sql-server

sql-server-2005