Question

我有一个表格城市

(Id, Name, ParentId)

其中ParentId是城市的Id（自相关表）

我想得到parentId为null（根）的城市如果名称匹配或子记录名称匹配我写了这个

declare @cities table (Id, Name, ParentId)

insert into @cities (Id , Name) 
select Id , Name from Cities
Where CHARINDEX(N'CD', Name) > 0 and ParentId is null 

insert into @cities (Id , Name) 
select Id , Name from Cities
Where Id in 
   (select distinct ParentId from Cities 
    where CHARINDEX(N'CD', Name) > 0 ParentId is not null) 
and ParentId is null 

select distinct * from @cities

我能做些什么来让它变得更快更好？编辑：

Id  | Name  | ParentId 
----------------------
1   | ABCD  | NULL
----------------------
2   | EFZX  | NULL
----------------------
3   | GHIJ  | NULL
----------------------
4   | MNOP  | 1
----------------------
5   | CDKL  | 2
----------------------
6   | QRST  | 3
----------------------

这应该返回：

Id  | Name  | ParentId 
----------------------
1   | ABCD  | NULL
----------------------
2   | EFZX  | NULL
----------------------

EDIT2：
第一个选择返回匹配名称为的城市第二个选择返回具有匹配子项的城市然后合并两个结果。

Answer 1

我可以用一个选择建议解决方案。我认为你想要父母和直系后代的结果。因此，您应该选择名称匹配的所有行＆＃39; CD＆＃39;

SELECT * FROM @cities
WHERE CHARINDEX(N'CD', Name) > 0

这会给你

1   ABCD    NULL
5   CDKL    2
6   CDKP    2

您希望仅选择父母，这就是为什么您需要在父级上进行左连接以获取父级为2的行

SELECT *  FROM @cities c1
LEFT JOIN @cities c2 ON c1.ParentId = c2.ID
WHERE CHARINDEX(N'CD', c1.Name) > 0

返回

1   ABCD    NULL    NULL    NULL    NULL
5   CDKL    2       2       EFZX    NULL
6   CDKP    2       2       EFZX    NULL

然后你在and (c1.ParentId is NULL OR (c1.ParentId IS NOT NULL AND c2.ParentId IS NULL))的第二位申请，只接纳父母和直系亲属。

 declare @cities table (Id int, Name NVARCHAR(MAX), ParentId INT null)

INSERT INTO @cities (Id, Name, ParentId) VALUES (1, 'ABCD', NULL)
INSERT INTO @cities (Id, Name, ParentId) VALUES (2, 'EFZX', NULL)
INSERT INTO @cities (Id, Name, ParentId) VALUES (3, 'GHIJ', NULL)
INSERT INTO @cities (Id, Name, ParentId) VALUES (4, 'MNOP', 1)
INSERT INTO @cities (Id, Name, ParentId) VALUES (5, 'CDKL', 2)
INSERT INTO @cities (Id, Name, ParentId) VALUES (6, 'CDKP', 2)




SELECT DISTINCT ISNULL(c2.Id, c1.Id), ISNULL(c2.Name, c1.Name)  FROM @cities c1
LEFT JOIN @cities c2 ON c1.ParentId = c2.ID
WHERE CHARINDEX(N'CD', c1.Name) > 0 and (c1.ParentId is NULL  OR (c1.ParentId IS NOT NULL AND c2.ParentId IS NULL))

Answer 2

示例代码

CREATE table #cities  (Id INT, Name VARCHAR(30), ParentId INT)


insert into #cities (Id, Name, ParentId) VALUES(1 , 'ABCD',NULL) 
insert into #cities (Id, Name, ParentId) VALUES(2 , 'EFZX',NULL) 
insert into #cities (Id, Name, ParentId) VALUES(3 , 'GHIJ',NULL) 
insert into #cities (Id, Name, ParentId) VALUES(4 , 'MNOP',1) 
insert into #cities (Id, Name, ParentId) VALUES(5 , 'CDKL',2) 
insert into #cities (Id, Name, ParentId) VALUES(6 , 'QRST',3)

<强> QUERY

;WITH CTE AS
(
    -- Select condition for parent
    SELECT Id, Name, ParentId,0 AS [LEVEL]
    FROM #cities --WHERE ParentId IS NULL --AND ID=1
    WHERE CHARINDEX(N'CD', Name) > 0 and ParentId is null 
    UNION ALL 
    SELECT C1.*,C2.[LEVEL]+1 
    FROM #cities C1
    JOIN CTE C2 ON C1.ParentId=C2.Id
)
-- Since you get only parent and children, you can filter children here
SELECT * 
FROM CTE
WHERE CHARINDEX(N'CD', Name) > 0 
OPTION(MAXRECURSION 0)

选择字段匹配或子记录字段是否匹配

2 个答案: