SQL案例声明与子选择

Question

select case when exists(
           select top 1 1 
           from dg_world_records wr (nolock) 
           where wr.gametypeid = 4 
           and wr.playerid = 1 
          ) 
    then totaltime = (select min(totaltime) from dg_world_records (nolock) where playerid = 1 and gametypeid = 4) 
    else totaltime = (select max(totaltime) from dg_world_records (nolock) where gametypeid = 4) 
    end 

我的猜测是这不能完成，但我想在sql case语句中做一个子选择。这可能吗？

我试图做基于发现或没有找到在表中的值的查找。我可以通过分解声明来做到这一点，但我想知道是否可以在一个声明中做到这一点。

下面是表模式：

CREATE TABLE [dbo].[DG_WORLD_RECORDS](
[WorldRecordId] [int] IDENTITY(1,1) NOT NULL, 
[GameTypeId] [int] NOT NULL, 
[PlayerId] [int] NOT NULL, 
[NumberOfValues] [int] NOT NULL, 
[TotalTime] [int] NOT NULL, 
[DateOfRecord] [datetime] NOT NULL, 
[GameId] [int] NULL, 
[UTCInserted] [datetime] NOT NULL CONSTRAINT [DF_DG_WORLD_RECORDSII_UTCInserted] DEFAULT (getutcdate()), 
[UTCUpdated] [datetime] NOT NULL CONSTRAINT [DF_DG_WORLD_RECORDSII_UTCUpdated] DEFAULT (getutcdate()), 
[SrvName] [varchar](30) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL CONSTRAINT [DF_DG_WORLD_RECORDSII_SrvName] DEFAULT (@@servername), 

约束[PK_DG_WORLD_RECORDS] PRIMARY KEY CLUSTERED （ [WorldRecordId] ASC ） ）

Answer 1

不知道您为什么要写这个疯狂的查询，但要回答你的问题，是的，它可以做，只动分配出的情况下声明：

select totaltime = CAST (
    case when exists(
    select * 
    from dg_world_records wr (nolock) 
    where wr.gametypeid = 4 and wr.playerid = 1) 
    then (select min(totaltime) from dg_world_records (nolock) where playerid = 1 and gametypeid = 4) 
    else (select max(totaltime) from dg_world_records (nolock) where gametypeid = 4) 
    end AS INT)