TSQL：即使条件不匹配，如何输出记录

Question

我有一个 temp table 有 3 列 "ID","Cost", "MaxCost"..下面是我的 select 声明 selects 行给定特定 ID..

        SELECT
            t.Cost 
            t.MaxCost
        FROM @temp t
        WHERE t.ID = @ID

我如何修改上述查询，以便即使给定的 ID 不存在它仍然输出 Cost = 0 & MaxCost = 0 的行

Answer 1

Select实际和默认记录，select第一个按重量排序。

select top (1)
  Cost,
  MaxCost
from (
  SELECT
    t.Cost 
    t.MaxCost,
    1 as takeme
  FROM @temp t
  WHERE t.ID = @ID

  union all

  select 0, 0, 0
) foo
order by
  foo.takeme desc

Answer 2

declare @table table (cost int); 
insert into @table values (2), (2), (3);

declare @findCost int = 1; 

select * from @table where cost = @findCost
union all
select 0 as cost from @table where cost = @findCost having count(*) = 0;

set @findCost = 2;

select * from @table where cost = @findCost
union all
select 0 as cost from @table where cost = @findCost having count(*) = 0;

TSQL：即使条件不匹配，如何输出记录

TSQL: How to ouput records even when where condition doesnt match

tsql

sql-server

sqlxml