用户关联匹配SQL查询？

Question

所以我有两个用户一个导师和一个导师。

我想根据他们的技能向导师显示导师名单。

所以登记将是一堆复选框该说的...

受指导者认为：

我需要

[] Branding 
[] Marketing 
[] Legal stuff 

导师帮忙看：

我的专长

[] Branding 
[] Marketing 
[] Legal stuff 

是否有一个SQL服务器查询来匹配这些家伙了基于2008年的共性？

希望这一切是有道理的：\

干杯

Answer 1

如何开头是这样的：

declare @Users as Table (UserId Int Identity, UserName VarChar(10), Mentor Bit) 
declare @Skills as Table (SkillId Int Identity, Skill VarChar(10)) 
declare @UserSkills as Table (UserId Int, SkillId Int) 

insert into @Users (UserName, Mentor) values ('Einstein', 1), ('Dilbert', 0), ('Marie', 1), ('The Fonz', 1) 
insert into @Skills (Skill) values ('Arithmetic'), ('Chemistry'), ('Dancing') 
insert into @UserSkills (UserId, SkillId) values 
    (1, 1), (1, 3), 
    (2, 1), (2, 3), 
    (3, 1), (3, 2), (3, 3), 
    (4, 3) 

-- All users. 
select U.*, S.* 
    from @Users as U inner join 
    @UserSkills as US on US.UserId = U.UserId inner join 
    @Skills as S on S.SkillId = US.SkillId 
    order by U.Mentor, U.UserName, S.Skill 

-- Matches for user 2. 
-- Should validate that they are not a mentor. 
declare @StudentId as Int = 2 
select UM.*, S.*, 
    (select count(42) from @UserSkills as USM inner join 
    @UserSkills as USS on USS.SkillId = USM.SkillId and USS.UserId = @StudentId and USM.UserId = UM.UserId) as 'MatchCount' 
    from @Users as UM inner join 
    @UserSkills as USM on USM.UserId = UM.UserId and UM.Mentor = 1 inner join 
    @Skills as S on S.SkillId = USM.SkillId inner join 
    @UserSkills as USS on USS.SkillId = USM.SkillId and USS.UserId = @StudentId 
    order by (select count(42) from @UserSkills as USM inner join 
    @UserSkills as USS on USS.SkillId = USM.SkillId and USS.UserId = @StudentId and USM.UserId = UM.UserId) desc, 
    UM.UserName, S.Skill 

Answer 2

这里有一个解决方案。请注意@UserSkill表中的is_requesting位。一个用户可以是一个技能的受指导者，另一个可以是导师。似乎是最合理的方法。

您可以通过再次连接到表格并使用某些有趣的字符串连接来扩展查询以包含每个关系的技能。

DECLARE @User TABLE 
(
    id INT IDENTITY (1,1), 
    name VARCHAR(100) 
) 

DECLARE @Skill TABLE 
(
    id INT IDENTITY(1,1), 
    name VARCHAR(100) 
) 

DECLARE @UserSkill TABLE 
(
    [user_id] INT, 
    skill_id INT, 
    is_requesting BIT -- true if mentee asking for help, false if mentor offering help 
) 

INSERT INTO @User 
SELECT 'Alice' 
UNION SELECT 'Bob' 
UNION SELECT 'Charlie' 
UNION SELECT 'Doug' 

SELECT * FROM @User 

INSERT INTO @Skill 
SELECT 'Branding' 
UNION SELECT 'Marketing' 
UNION SELECT 'Legal' 

SELECT * FROM @Skill 

INSERT INTO @UserSkill 
SELECT 1, 1, 1 
UNION SELECT 1, 2, 1 
UNION SELECT 2, 2, 1 
UNION SELECT 2, 3, 0 
UNION SELECT 3, 1, 0 
UNION SELECT 3, 2, 0 
UNION SELECT 4, 2, 0 
UNION SELECT 4, 3, 0 

SELECT * 
FROM @User u 
JOIN @UserSkill us 
    ON u.id = us.[user_id] 
JOIN @Skill s 
    ON us.skill_id = s.id 

DECLARE @skill_string VARCHAR(1000) 

SELECT eu.name AS [Mentee] 
    , ru.name AS [Mentor] 
    , COUNT(*) AS [Commonality] 
FROM @User eu -- 'eu' for mente'e' 'u'ser 
JOIN @UserSkill eus 
    ON eu.id = eus.[user_id] 
    AND eus.is_requesting = 1 
JOIN @Skill es 
    ON eus.skill_id = es.id 
JOIN @UserSkill rus 
    ON eus.skill_id = rus.skill_id 
    AND rus.is_requesting = 0 
JOIN @User ru -- 'r' for mento'r' 'u'ser 
    ON rus.[user_id] = ru.id 
GROUP BY eu.name, ru.name 
ORDER BY eu.name, ru.name