我有一个表ALPHA,包含2个字段GroupId,成员:
GroupId | Member;
A1----------A;
A1----------B;
A1----------C;
A2----------A;
A2----------B;
A3----------A;
A3----------D;
A3----------E;
目标:鉴于-A,B,C的输入,我必须查询该表以查找是否存在这组精确成员的GroupId。所以,这就是我打算做的事情:
我打算写一个存储过程,并以某种方式实现目标。但是,我的问题可以在单个查询中实现......也许是单个自联接。
澄清:(A,B,C)的集合是A1独有的。如果输入(A,B,C,D),则查询不应返回A1。
答案 0 :(得分:4)
SELECT GroupID
FROM ALPHA
WHERE Member IN ('A', 'B', 'C')
GROUP BY GroupID
HAVING COUNT(*) = 3
这依赖于您在IN子句中写出成员列表并在HAVING子句中设置成员列表中的(不同)条目数。如果你不能这样生成SQL,那么你必须更加努力。
正如早期评论中所指出的,这也依赖于您希望A,B,C(以及可能还有其他)三者都是该组成员的群体的解释。获得'组中恰好包含三个人,即A,B,C'的一种方式,不一定是最好的方法,是使用:
SELECT GroupID
FROM ALPHA A1
WHERE Member IN ('A', 'B', 'C')
AND 3 = (SELECT COUNT(*) FROM ALPHA A2 WHERE A2.GroupID = A1.GroupID)
GROUP BY GroupID
HAVING COUNT(*) = 3
这明确检查组中的总人数是3,成员是A,B和C(假设Alpha上有唯一约束(GroupID,Member),以便成员不能被列为属于同一组的两次。)
答案 1 :(得分:2)
SELECT DISTINCT aa.GroupId
FROM Alpha aa
JOIN Alpha ab ON (aa.GroupId = ab.GroupId)
JOIN Alpha ac ON (aa.GroupId = ac.GroupId)
LEFT OUTER JOIN Alpha ax ON (aa.GroupId = ax.GroupId AND ax.Member NOT IN ('A', 'B', 'C')
WHERE aa.Member = 'A' AND ab.Member = 'B' AND ac.Member = 'C'
AND ax.GroupId IS NULL;
还有涉及GROUP BY
的解决方案,但我发现JOIN
解决方案通常具有更好的性能。我通常在MySQL工作,我理解MS SQL Server更擅长分组查询。因此,尝试两种解决方案,看看哪种解决方案最适合您使用的RDBMS品牌。
答案 2 :(得分:2)
到目前为止给出的答案假设Member字段对于任何给定的GroupID都是唯一的。在工作中,我所做的并非如此。而且,如果该小组拥有您正在寻找的内容,还有一些额外内容,那么您需要将该小组排除在外。
SELECT
[Alpha].GroupID
FROM
[Alpha]
GROUP BY
[Alpha].GroupID
HAVING
SUM(CASE WHEN [alpha].Member IN ('A','B','C') THEN 1 ELSE 0 END) = 3
AND MIN(CASE WHEN [alpha].Member IN ('A','B','C') THEN 1 ELSE 0 END) = 1
您还可以将IN子句替换为包含您正在搜索的成员的表的连接...
SELECT
[Alpha].GroupID
FROM
[Alpha]
LEFT JOIN
[Search]
ON [Search].Member
GROUP BY
[Alpha].GroupID
HAVING
SUM(CASE WHEN [alpha].Member = [search].Member THEN 1 ELSE 0 END) = (SELECT COUNT(*) FROM [search])
AND MIN(CASE WHEN [alpha].Member = [search].Member THEN 1 ELSE 0 END) = 1
答案 3 :(得分:2)
试试这个:
declare @YourTable table (GroupID char(2),Member char(1))
insert into @YourTable values ('A1','A')
insert into @YourTable values ('A1','B')
insert into @YourTable values ('A1','C')
insert into @YourTable values ('A2','A')
insert into @YourTable values ('A2','B')
insert into @YourTable values ('A3','A')
insert into @YourTable values ('A3','D')
insert into @YourTable values ('A3','E')
insert into @YourTable values ('A5','A')
insert into @YourTable values ('A5','B')
insert into @YourTable values ('A5','C')
insert into @YourTable values ('A5','D')
SELECT t1.GroupID
FROM @YourTable t1
LEFT OUTER JOIN @YourTable t2 ON t1.GroupID=t2.GroupID AND t2.Member NOT IN ('A', 'B', 'C')
WHERE t1.Member IN ('A', 'B', 'C')
AND t2.GroupID IS NULL
GROUP BY t1.GroupID
HAVING COUNT(*) = 3
输出:
GroupID
-------
A1
(1 row(s) affected)
这是一个完整的解决方案:
在使用我的功能之前,您需要设置一个“帮助程序”表,每个数据库只需执行一次这样的操作:
CREATE TABLE Numbers
(Number int NOT NULL,
CONSTRAINT PK_Numbers PRIMARY KEY CLUSTERED (Number ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
DECLARE @x int
SET @x=0
WHILE @x<8000
BEGIN
SET @x=@x+1
INSERT INTO Numbers VALUES (@x)
END
使用此函数来分割您的字符串,该字符串不会循环且非常快:
CREATE FUNCTION [dbo].[FN_ListToTable]
(
@SplitOn char(1) --REQUIRED, the character to split the @List string on
,@List varchar(8000) --REQUIRED, the list to split apart
)
RETURNS
@ParsedList table
(
ListValue varchar(500)
)
AS
BEGIN
/**
Takes the given @List string and splits it apart based on the given @SplitOn character.
A table is returned, one row per split item, with a column name "ListValue".
This function workes for fixed or variable lenght items.
Empty and null items will not be included in the results set.
Returns a table, one row per item in the list, with a column name "ListValue"
EXAMPLE:
----------
SELECT * FROM dbo.FN_ListToTable(',','1,12,123,1234,54321,6,A,*,|||,,,,B')
returns:
ListValue
-----------
1
12
123
1234
54321
6
A
*
|||
B
(10 row(s) affected)
**/
----------------
--SINGLE QUERY-- --this will not return empty rows
----------------
INSERT INTO @ParsedList
(ListValue)
SELECT
ListValue
FROM (SELECT
LTRIM(RTRIM(SUBSTRING(List2, number+1, CHARINDEX(@SplitOn, List2, number+1)-number - 1))) AS ListValue
FROM (
SELECT @SplitOn + @List + @SplitOn AS List2
) AS dt
INNER JOIN Numbers n ON n.Number < LEN(dt.List2)
WHERE SUBSTRING(List2, number, 1) = @SplitOn
) dt2
WHERE ListValue IS NOT NULL AND ListValue!=''
RETURN
END --Function FN_ListToTable
您现在可以使用这样的函数来查询任何列表:
DECLARE @List varchar(100)
SET @List='A,B,C'
declare @YourTable table (GroupID char(2),Member char(1))
insert into @YourTable values ('A1','A')
insert into @YourTable values ('A1','B')
insert into @YourTable values ('A1','C')
insert into @YourTable values ('A2','A')
insert into @YourTable values ('A2','B')
insert into @YourTable values ('A3','A')
insert into @YourTable values ('A3','D')
insert into @YourTable values ('A3','E')
insert into @YourTable values ('A5','A')
insert into @YourTable values ('A5','B')
insert into @YourTable values ('A5','C')
insert into @YourTable values ('A5','D')
SELECT t1.GroupID
FROM @YourTable t1
LEFT OUTER JOIN @YourTable t2 ON t1.GroupID=t2.GroupID AND t2.Member NOT IN (SELECT ListValue FROM dbo.FN_ListToTable(',',@List))
WHERE t1.Member IN (SELECT ListValue FROM dbo.FN_ListToTable(',',@List))
AND t2.GroupID IS NULL
GROUP BY t1.GroupID
HAVING COUNT(*) = (SELECT COUNT(*) FROM dbo.FN_ListToTable(',',@List))
输出:
GroupID
-------
A1
答案 4 :(得分:1)
从ALPHA中选择* 会员在哪里( 从ALPHA中选择会员 小组成员 有COUNT(*)= 3)
答案 5 :(得分:1)
试试这个:
SELECT GroupId
FROM ALPHA
GROUP BY GroupId
HAVING SUM(CASE WHEN Member='A' THEN 1.0
WHEN Member='B' THEN 2.0
WHEN Member='C' THEN 4.0
ELSE 7.31415
END) = 7.0
答案 6 :(得分:0)
我的建议是将分隔的字符串解析为临时表,然后尝试这样的事情。
create table #temp(member varchar(10))
create table #groups
(
groupID varchar(2),
member char(1)
)
--#temp holds the members from your delimited string.
--#groups holds your relationships.
select distinct groupID
from #groups
where
(select count(*) from #groups i, #temp t
where i.member = t.member and i.groupID = #groups.groupID) =
(select count(*) from #temp)