我的数据库中的一个表包含如下数据,
TBLlocations
-------------------------------------------------------
LocationId LocationName RegisteredUnder Type
--------------------------------------------------------
LOC100 Location1 0 0
LOC201 Location2 LOC100 2
LOC102 Location3 LOC201 1
LOC302 Location4 LOC201 1
LOC103 Location5 LOC201 1
LOC104 Location6 LOC201 1
LOC105 Location7 LOC104 1
LOC106 Location8 LOC105 1
LOC107 Location9 LOC106 1
现在我必须从上表中选择位置,这样我的查询将返回第一级位置,即;考虑到上表,我的查询必须返回位置其类型为"1",并且应该是类型为"0"的一级子位置。从上表中,位置3到6是一级位置,因此查询应返回以下内容:
---------------
Location3
Location4
Location5
Location6
我试图加入为"Type"提供条件的同一个表。这是我构建的查询:
Select Distinct t1.LocationId,t1.LocationName,t1.RegisteredUnder from TBLlocations t1
join TBLlocations t2 on t2.RegisteredUnder!=t1.LocationId
where t1.Type='1' and t2.Type='1'
order by t1.RegisteredUnder
上面的查询返回了类型"1"下的所有位置,如下所示:
--------------------------------------------------
LocationId LocationName RegisteredUnder
--------------------------------------------------
LOC102 Location3 LOC201
LOC302 Location4 LOC201
LOC103 Location5 LOC201
LOC104 Location6 LOC201
LOC105 Location7 LOC104
LOC106 Location8 LOC105
LOC107 Location9 LOC106
因此,我需要一个能够返回确切结果的查询。我在查询中唯一可以使用的参数是"Type",并且始终为"1"。
附言:我使用的是SQL Server 2008。
问题更改后
Declare @a table (LocationId Varchar(100), LocationName Varchar(100), RegisteredUnder Varchar(100), Type int)
Insert into @a Values('LOC100','Location1','0',0)
Insert into @a Values('LOC201','Location2','LOC100',2)
Insert into @a Values('LOC102','Location3','LOC201',1)
Insert into @a Values('LOC302','Location4','LOC201',1)
Insert into @a Values('LOC103','Location5','LOC201',1)
Insert into @a Values('LOC104','Location6','LOC201',1)
Insert into @a Values('LOC105','Location7','LOC104',1)
Insert into @a Values('LOC106','Location8','LOC105',1)
Insert into @a Values('LOC107','Location9','LOC106',1)
;With CTE as
(
Select 0 as level,* from @a where Type=1
UNION ALL
Select c.Level+1, a.* from @a a
join CTE c on c.LocationId=a.RegisteredUnder and a.Type=1
)
Select c1.* from CTE c1
Left Join CTE c2 on c2.LocationId=c1.LocationId and c2.level>0
where c2.LocationId is NULL
order by LEVEL desc,LocationName
问题前的答案改变了
Declare @a table (LocationId Varchar(100), LocationName Varchar(100), RegisteredUnder Varchar(100), Type int)
Insert into @a Values('LOC100','Location1','0',0)
Insert into @a Values('LOC201','Location2','LOC100',2)
Insert into @a Values('LOC102','Location3','LOC201',1)
Insert into @a Values('LOC302','Location4','LOC201',1)
Insert into @a Values('LOC103','Location5','LOC201',1)
Insert into @a Values('LOC104','Location6','LOC201',1)
Insert into @a Values('LOC105','Location7','LOC104',1)
Insert into @a Values('LOC106','Location8','LOC105',1)
Insert into @a Values('LOC107','Location9','LOC106',1)
;With CTE as
(
Select 0 as level,* from @a where RegisteredUnder='LOC201'
UNION ALL
Select c.Level+1, a.* from @a a
join CTE c on c.RegisteredUnder=a.LocationId
)
Select DISTINCT * from CTE
where level<2
order by LEVEL desc, LocationName