Question

我有两个表Master - Detail并试图根据输入参数找到更相关的结果

Create Table #Master(MasterId int, Method varchar(100))
Insert Into #Master Values(1,'MasterDefault')

Create Table #Detail(Id int, MasterId int,ATypeId int, BTypeId int,CTypeId int,DetailMethod varchar(100))
Insert Into #Detail
Values(1,1,1,1,1,'Detail All'),
      (2,1,null,1,1,'Detail ATypeId null'),
      (3,1,null,null,1,'Detail ATypeId and Btype null'),
      (4,1,null,null,null,'Detail all null')

开始下面的内容（我想要找的只是方法，无论是主人还是细节）

declare @Id int =1,
        @AtypeId int =1,
        @BtypeId int=1,
        @CtypeId int =1

Select *
from #Master M
    left outer join #Detail D on M.MasterId = D.MasterId
Where M.MasterId = @Id
    AND ((D.ATypeId=@AtypeId) OR (D.ATypeId IS NULL))     
    AND ((D.BTypeId=@BtypeId) OR (D.BTypeId IS NULL))     
    AND ((D.CTypeId=@CtypeId) OR (D.CTypeId IS NULL))

在这种情况下，想要返回Detail - Id 1记录，因为所有输入都与详细信息row1匹配

ID参数如下

declare @Id int =1,
        @AtypeId int =null,
        @BtypeId int=1,
        @CtypeId int =1

期望来自详细信息的行与Id 2

有关实现此目的的任何帮助

Answer 1

简单AND/OR逻辑对您有用。

SELECT *
FROM   #Master M
       LEFT OUTER JOIN #Detail D
                    ON M.MasterId = D.MasterId
                       AND ( D.ATypeId = @AtypeId
                              OR ( @AtypeId IS NULL
                                   AND AtypeId IS NULL ) )
                       AND ( D.BTypeId = @BtypeId
                              OR ( @BtypeId IS NULL
                                   AND BtypeId IS NULL ) )
                       AND ( D.CTypeId = @CtypeId
                              OR ( @CtypeId IS NULL
                                   AND CtypeId IS NULL ) )
WHERE  M.MasterId = @Id

注意：由于您使用了ON，我已将右表过滤器移至LEFT OUTER JOIN条件。当您使用LEFT OUTER JOIN并过滤Where子句中的右表记录时，它将隐式转换为INNER JOIN

查找最具体的记录 - SQL

1 个答案: