Question

我有一个返回结果集的SQL脚本，要求是如果以下脚本未产生任何结果，则返回带有默认值的默认结果集。它的列名应与以下脚本相同

 -- Return final results
    SELECT  
        p.worked                                                                           [AccountsWorked],
        p.rcmade                                                                       [RPC's],
        p.obtained                                                                             [PTPCount],
        p.amount                                                                          [PTPValue], 
                                                                                                [PreviousDayPTPValue]

    FROM
        @tab_performance p JOIN
        dbo.user usr ON
            (p.usr_code = usr.usr_code) JOIN
        dbo.team tme ON 
            (tme.tme_id = usr.tme_id)   
            AND p.usr_code = @usr_code

如果没有返回行，我需要返回默认结果集。因此，所有列均应返回NULL或任何默认值。

我尝试了条件选择语句而没有任何运气，我也尝试了@@ ROWCOUNT

Answer 1

您可以使用以下默认值向现有查询中添加union all选择：

<your existing query>

union all

select null accounts_worked, null right_contacts_made, null ppts_obtained .....
where not exists(
select *
from @tab_performance p JOIN
        dbo.TR_USR_User usr ON
            (p.usr_code = usr.usr_code) JOIN
        dbo.TR_TME_Team tme ON 
            (tme.tme_id = usr.tme_id)   
            AND p.usr_code = @usr_code
)

如果您的where不过滤掉inner joins中的任何行，则@tab_performance子句可以进一步简化：

<your existing query>

union all 

select null accounts_worked, null right_contacts_made, null ppts_obtained .....
where not exists(
select *
from @tab_performance
where usr_code = @usr_code
)

Answer 2

我会使用 WITH 和 UNION ALL

Drop  table if exists #test
create table #test (
    Column1 int null,
    Column2 varchar(50) null
);

--INSERT INTO [#test] (Column1,Column2)
--VALUES        
--        (1, 'test'),
--        (2,'test2'),
--        (3,'test3');

WITH qry AS (
   select Column1, Column2 from #test
)
select * from qry
UNION ALL
select NULL as Colum1, null as Column2 where (select COUNT(*) from qry) = 0

如果没有返回行，则SQL返回默认值

2 个答案: