Question

我有一个表 digital_calendar_event ，其列为： dce_date ， dce_event_name ， dce_event_icone

数据显示在可编辑的Datagrid中，可以在其中修改事件名称或Icone。我不知道它是更新还是插入（我不想使用ID，这里的日期是唯一的主键）我听说Merge函数可以检查值是否存在，这里我的主键是 dce_date

另外，我需要检测用户是否已删除数据网格中的值（ dce_event_name 或 dce_event_icone ）

我想使用合并功能，但是我只有一个表，在合并中似乎需要一个源表...

编辑：我使用了IF EXIST语句，但是在 ELSE 部分，我似乎无法输入CASE WHEN语句

IF EXISTS (SELECT dce_date FROM digital_calendar_event where dce_date = @CurrentDate)
UPDATE digital_calendar_event set dce_event_name = @EventName, dce_event_icone = @EventIcone
--- incorrect syntax near 'CASE'
ELSE CASE 
   WHEN @EventName ='' and @EventIcone = '' THEN DELETE FROM digital_calendar_event WHERE dce_date = @CurrentDate
   WHEN @EventName <> '' or @EventIcone <> '' THEN INSERT INTO digital_calendar_event (dce_date, dce_event_name, dce_event_icone) VALUES(@CurrentDate, @EventName , @EventIcone)
END

如何这样做？我编写的SQL代码正是我所需要的，但是如果不起作用...

Answer 1

嗨，尝试使用以下查询-

IF EXISTS (SELECT dce_date FROM digital_calendar_event where dce_date = @CurrentDate)
Begin
UPDATE digital_calendar_event set dce_event_name = @EventName, dce_event_icone = @EventIcone

ELSE 

if  @EventName ='' and @EventIcone = '' 
Begin
DELETE FROM digital_calendar_event WHERE dce_date = @CurrentDate

ENd


   Else IF @EventName <> '' or @EventIcone <> '' 
   Begin
   INSERT INTO digital_calendar_event (dce_date, dce_event_name, dce_event_icone) VALUES(@CurrentDate, @EventName , @EventIcone)

   END
END

Answer 2

感谢@Deepak Kumar，这是答案：

IF EXISTS (SELECT dce_date FROM digital_calendar_event where dce_date = @CurrentDate)
BEGIN
    IF  @EventName ='' and @EventIcone = '' 
        BEGIN
        DELETE FROM digital_calendar_event WHERE dce_date = @CurrentDate
        END
   ELSE UPDATE digital_calendar_event set dce_event_name = @EventName, dce_event_icone = @EventIcone
END
ELSE-- else of if exists
  BEGIN
    IF @EventName <> '' or @EventIcone <> '' 
    INSERT INTO digital_calendar_event (dce_date, dce_event_name, dce_event_icone) VALUES(@CurrentDate, @EventName , @EventIcone)
  END

使用SQL Server 2016合并功能

2 个答案: