使用SQL Server 2008检查表中是否存在ID

Question

我在使用SQL Server 2008中的select语句时遇到了一些麻烦。我正在构建售票应用程序网站，并且需要确保无法搜索已售出的票。 这是我的SQL存储过程：

    spGetSeatBySection
    @SectionID int
    AS
    SELECT
    [SeatID],
    [SectionID],
    [SeatName],
    [SeatPrice],
    [SeatDesc],
    [SeatIsActive],
  FROM [myDataBase].[dbo].[Seats]
  WHERE SectionID = @SectionID 
  AND SeatIsActive = 1 
  AND **IF EXISTS CLAUSE**;

我已经尝试了一些其他的方法，例如if exist（'table_name，'column_name'）。 还有另一种无需重新设计SELECT语句即可检查此问题的方法吗？

Answer 1

EXISTS就是这样的 ：

    SELECT
    [SeatID],
    [SectionID],
    [SeatName],
    [SeatPrice],
    [SeatDesc],
    [SeatIsActive],
  FROM [myDataBase].[dbo].[Seats]
  WHERE SectionID = @SectionID 
  AND SeatIsActive = 1 
  AND EXISTS (SELECT o.SeatID 
              FROM OrderItems o
              WHERE o.SeatID = [Seats].SeatID )

您可能可以做到这一点：

     SELECT
    s.[SeatID],
    s.[SectionID],
    s.[SeatName],
    s.[SeatPrice],
    s.[SeatDesc],
    s.[SeatIsActive],
  FROM [myDataBase].[dbo].[Seats] s
       INNER JOIN OrderItems o ON o.SeatID = s.SeatID 
  WHERE s.SectionID = @SectionID 
  AND s.SeatIsActive = 1