如何在 SQL 服务器中的 case 语句内的 then 子句中传递 2 个参数

Question

我正在开发一个 scholl 项目，我创建了一个存储过程，需要在 THEN 子句中传递两个参数，当变量 @tempo 是天时，我想 select 月和日.

CREATE OR ALTER PROCEDURE tentativa1 
    @tempo as nvarchar(30),
    @ap_id int
AS
    SELECT
        L_AccessPoint.ap_id, ap_name, 
        COUNT(*) AS NumeroAcessos, year,
        CASE
            WHEN @tempo = 'month' THEN month 
            ELSE NULL 
        END AS 'MES',
        CASE 
            WHEN @tempo = 'day' THEN day 
            ELSE NULL 
        END AS 'DIA'
    FROM 
        L_AccessPoint 
    INNER JOIN 
        F_Session ON L_AccessPoint.ap_id = F_Session.ap_id
    WHERE 
        L_AccessPoint.ap_id = @ap_id
    GROUP BY
        L_AccessPoint.ap_id, ap_name, year,
        CASE WHEN @tempo = 'month' THEN month ELSE NULL END,
        CASE WHEN @tempo ='day' THEN day ELSE NULL END
    ORDER BY
        L_AccessPoint.ap_id, year,
        CASE WHEN @tempo ='month' THEN month ELSE NULL END,
        CASE WHEN @tempo ='day' THEN day ELSE NULL END

是否可以做出类似的东西：

CASE 
    WHEN @tempo = 'day' THEN month, day 
    ELSE NULL 
END AS 'DIA'

如果 @tempo 是日，我必须按年、月和日分组，否则如果 @tempo 是年，我只需要按年分组。如果我传递 @tempo 等于天，结果是按年和天分组，将一年内每个月的所有第 1 天分组在同一行中。像这样Wrong result。有什么方法可以正确做到这一点？？

Answer 1

因此，经过一些测试后，我可以通过将 case when 替换为 if 和 else if 来正确地执行该过程，结果保持这样：

CREATE or alter PROCEDURE testeSessoes
        @tempo as nvarchar(30),
        @data_ini as date,
        @data_fin as date
AS
BEGIN
IF @tempo = 'year'
Begin
Select L_AccessPoint.ap_id, ap_name, COUNT(*) AS NumeroAcessos, year
FROM L_AccessPoint INNER JOIN F_Session ON L_AccessPoint.ap_id = F_Session.ap_id
WHERE F_Session.ts between @data_ini and @data_fin 
Group by    L_AccessPoint.ap_id, ap_name, year
order by L_AccessPoint.ap_id ASC, year DESC
END
ELSE
IF @tempo='month'
Begin
Select L_AccessPoint.ap_id, ap_name, COUNT(*) AS NumeroAcessos, year,month
FROM L_AccessPoint INNER JOIN F_Session ON L_AccessPoint.ap_id = F_Session.ap_id
WHERE F_Session.ts between @data_ini and @data_fin
Group by    L_AccessPoint.ap_id, ap_name, year,month
order by L_AccessPoint.ap_id ASC, year DESC,month DESC
END
else
Begin
Select L_AccessPoint.ap_id, ap_name, COUNT(*) AS NumeroAcessos, year,month,day
FROM L_AccessPoint INNER JOIN F_Session ON L_AccessPoint.ap_id = F_Session.ap_id
WHERE F_Session.ts between @data_ini and @data_fin
Group by    L_AccessPoint.ap_id, ap_name, year,month,day
order by L_AccessPoint.ap_id ASC, year DESC,month DESC,day DESC
END
END

我创建了 3 个查询 returns 并按照我想要的方式进行分组。

感谢所有试图帮助我的人。

如何在 SQL 服务器中的 case 语句内的 then 子句中传递 2 个参数

How to pass 2 parameters in then clause inside case statement in SQL Server

sql

sql-server

stored-procedures