Question

我有一个存储过程，其中包含三个不同的查询，这些查询的返回值取决于接收到的变量。

它们基本上返回相同的数据，只是更改WHERE子句：

查询：

 IF @DesignType = 'BDCD'
            BEGIN
               SELECT
                    [DT].[DesignTypeGuid]
                   , [DT].[Name]
                   , [DT].[Abbreviation]
                   , CONVERT(BIT , IIF([DT].[DesignTypeGuid] = @ContractedDocument , 1 , 0)) AS [EnforceBaseOnPrevious]
                   , [DT].[Order]
                    FROM [DesignType] AS [DT]
                    WHERE [DT].[IsActive] = 1
                         AND ([DT].[DesignTypeGuid] != IIF(@DesignTypeGuid = @ContractedDocument , @BidDocument , @ContractedDocument))
                         AND [DT].[DesignTypeGuid] != @ChangeOrder
                         AND [DT].[DesignTypeGuid] != @AddedPart
                    ORDER BY
                            [DT].[Order]
            END
               ELSE
            BEGIN
               IF @DesignType = 'CO'
               BEGIN
                  SELECT
                        [DT].[DesignTypeGuid]
                      , [DT].[Name]
                      , [DT].[Abbreviation]
                      , 0 AS [EnforceBaseOnPrevious]
                      , [DT].[Order]
                        FROM [DesignType] AS [DT]
                        WHERE [DT].[IsActive] = 1
                            AND [DT].[DesignTypeGuid] = @ChangeOrder
                        ORDER BY
                               [DT].[Order]
               END
                  ELSE
               BEGIN
                  IF @DesignType = 'AP'
                  BEGIN
                     SELECT
                           [DT].[DesignTypeGuid]
                         , [DT].[Name]
                         , [DT].[Abbreviation]
                         , 0 AS [EnforceBaseOnPrevious]
                         , [DT].[Order]
                           FROM [DesignType] AS [DT]
                           WHERE [DT].[IsActive] = 1
                                AND [DT].[DesignTypeGuid] = @AddedPart
                           ORDER BY
                                  [DT].[Order]
                  END

有什么方法可以优化它，并通过简单的SELECT来完成，而是根据DesignType变量进行3种不同的处理？问候

Answer 1

不确定性能，但查询绝对可以写为

              SELECT
                [DT].[DesignTypeGuid]
               , [DT].[Name]
               , [DT].[Abbreviation]
               , CASE @DesignType WHEN 'BDCD' THEN CONVERT(BIT , IIF([DT].[DesignTypeGuid] = @ContractedDocument , 1 , 0)) ELSE 0 END AS [EnforceBaseOnPrevious]
               , [DT].[Order]
                FROM [DesignType] AS [DT]
                WHERE [DT].[IsActive] = 1
                     AND (
                            ( 
                                @DesignType = 'BDCD' AND [DT].[DesignTypeGuid] NOT IN ( IIF(@DesignTypeGuid = @ContractedDocument , @BidDocument , @ContractedDocument),@ChangeOrder,@AddedPart)
                            )
                            OR 
                            ( 
                                @DesignType = 'CO' AND [DT].[DesignTypeGuid] = @ChangeOrder
                            )
                            OR
                            (
                                @DesignType = 'AP' AND [DT].[DesignTypeGuid] = @AddedPart
                            )
                      )
                ORDER BY
                        [DT].[Order]

优化按条件分隔的多个查询

1 个答案: