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MS-SQL join queries based on common (not exact) results

Posted on 2013-12-31
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Last Modified: 2014-01-03
Query1 returns names and skills, Query2 returns jobs and required skills

Query1            
Name1      skill1      
Name2      skill1
Name2      skill2
Name3      skill2

Query2
Job1      skill1
Job2      skill1
Job2      skill2
Job3      skill2

The desired final result would be a list of names and the jobs
Name1      Job1
Name2      Job1
Name2      Job2
Name2      Job3
Name3      Job3
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Question by:rlarian
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14 Comments
 
LVL 21

Expert Comment

by:Dale Burrell
ID: 39749130
select Q1.Name, Q2.Job
from Query1 Q1, Query2 Q2
where Q1.Skill = Q2.Skill

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Author Comment

by:rlarian
ID: 39752554
problem is where Name has one of the skills of Job, it shows up in the results. I need the Name to match to a Job only if they have all the skills of the Job.


      IF OBJECT_ID('tempdb..#names') IS NOT NULL DROP TABLE #names
      CREATE TABLE #names(
      name varchar(30),
      skill int)      
      
      IF OBJECT_ID('tempdb..#jobs') IS NOT NULL DROP TABLE #jobs
      CREATE TABLE #jobs(
      job varchar(30),
      skill int)      
      
      INSERT INTO #names
      SELECT 'name1', 1 UNION ALL
      SELECT 'name2', 1 UNION ALL
      SELECT 'name2', 2 UNION ALL
      SELECT 'name3', 2
      
      INSERT INTO #jobs
      SELECT 'job1', 1 UNION ALL
      SELECT 'job2', 1 UNION ALL
      SELECT 'job2', 2 UNION ALL
      SELECT 'job3', 2
      
      SELECT Q1.name, Q2.job
      FROM (SELECT * FROM #names) Q1, (SELECT * FROM #jobs) Q2
      WHERE Q1.skill = Q2.skill
      ORDER BY Q1.name
      
      DROP TABLE #names
      DROP TABLE #jobs

RESULTS:
name1      job1
name1      job2 [should not match]
name2      job1
name2      job2 [should only match once]
name2      job2 [should only match once]
name2      job3
name3      job2 [should not match]
name3      job3
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LVL 21

Accepted Solution

by:
Dale Burrell earned 500 total points
ID: 39752623
So just a minor requirement you forgot to mention :)

The solution follows, but I would imagine if you have normalised you tables correctly you will  actually have 4 tables rather then two, i.e.

Person, PersonSkill, Job, JobSkill - if you had those 2 tables the following query would actually be simpler because you wouldn't need to find the unique people and jobs to start with.

declare @Name table (Name varchar(30), Skill int)
declare @Job table (Job varchar(30), Skill int)

insert into @Name (Name, Skill)
 select 'name1', 1 UNION ALL
 select 'name2', 1 UNION ALL
 select 'name2', 2 UNION ALL
 select 'name3', 2 
      
insert into @Job (Job, Skill)
  select 'job1', 1 UNION ALL
  select 'job2', 1 UNION ALL
  select 'job2', 2 UNION ALL
  select 'job3', 2 

select N.Name, J.Job
from (
  select Job
  from @Job
  group by Job
) J, (
  select Name
  from @Name
  group by Name
) N
where not exists (
  select 1
  from @Job J1
  where J1.Job = J.Job
  and not exists (select 1 from @Name N1 where N1.Name = N.Name and N1.Skill = J1.Skill)
)
order by N.Name, J.Job

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Expert Comment

by:Sharath
ID: 39752677
You did not mention your SQL version. I hope you are working on 2005 or later. If so, you can try this query.
;with names as (
select distinct t1.name,rtrim(substring(isnull((select ','+convert(varchar,t2.skill) from #names t2 where t1.name = t2.name for xml path('')),' '),2,2000)) skill
 from #names t1)
 ,jobs as ( 
select distinct t1.job,rtrim(substring(isnull((select ','+convert(varchar,t2.skill) from #jobs t2 where t1.job = t2.job for xml path('')),' '),2,2000)) skill
 from #jobs t1) 
select n.name,j.job
   from names n
   join jobs j on n.skill like '%'+j.skill+'%'

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IF OBJECT_ID('tempdb..#names') IS NOT NULL DROP TABLE #names
CREATE TABLE #names(
name varchar(30),
skill int)      
      
IF OBJECT_ID('tempdb..#jobs') IS NOT NULL DROP TABLE #jobs
CREATE TABLE #jobs(
job varchar(30),
skill int)      
      
INSERT INTO #names
SELECT 'name1', 1 UNION ALL
SELECT 'name2', 1 UNION ALL
SELECT 'name2', 2 UNION ALL
SELECT 'name3', 2 
      
INSERT INTO #jobs
SELECT 'job1', 1 UNION ALL
SELECT 'job2', 1 UNION ALL
SELECT 'job2', 2 UNION ALL
SELECT 'job3', 2 
      
;with names as (
select distinct t1.name,rtrim(substring(isnull((select ','+convert(varchar,t2.skill) from #names t2 where t1.name = t2.name for xml path('')),' '),2,2000)) skill
 from #names t1)
 ,jobs as ( 
select distinct t1.job,rtrim(substring(isnull((select ','+convert(varchar,t2.skill) from #jobs t2 where t1.job = t2.job for xml path('')),' '),2,2000)) skill
 from #jobs t1) 
select n.name,j.job
   from names n
   join jobs j on n.skill like '%'+j.skill+'%'

DROP TABLE #names
DROP TABLE #jobs
/*
name	job
name1	job1
name2	job1
name2	job2
name2	job3
name3	job3
*/   

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Author Comment

by:rlarian
ID: 39752878
SQL 2008R2

if i enter extra jobs, not in order, it doesn't return the correct result. job 5 below inserted with skill 2, 1, 4 will not match name2. if is inserted as 1,2,4  it will match.

     
INSERT INTO #names
SELECT 'name1', 1 UNION ALL
SELECT 'name2', 1 UNION ALL
SELECT 'name2', 2 UNION ALL
SELECT 'name2', 4 UNION ALL
SELECT 'name2', 5 UNION ALL
SELECT 'name3', 2
     
INSERT INTO #jobs
SELECT 'job1', 1 UNION ALL
SELECT 'job2', 1 UNION ALL
SELECT 'job2', 2 UNION ALL
SELECT 'job3', 2 UNION ALL
SELECT 'job4', 3 UNION ALL
SELECT 'job5', 2 UNION ALL  --
SELECT 'job5', 1 UNION ALL   --
SELECT 'job5', 4
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LVL 21

Expert Comment

by:Dale Burrell
ID: 39752898
You can't be running the code I posted because insert order has no effect on the query I gave. With you new data I get the following (which I believe is correct) regardless of what order I insert it.

name1      job1
name2      job1
name2      job2
name2      job3
name2      job5
name3      job3
0
 
LVL 4

Author Comment

by:rlarian
ID: 39752905
here is the code i'm running. i thought it was a bit strange.

IF OBJECT_ID('tempdb..#names') IS NOT NULL DROP TABLE #names
CREATE TABLE #names(
name varchar(30),
skill int)      
     
IF OBJECT_ID('tempdb..#jobs') IS NOT NULL DROP TABLE #jobs
CREATE TABLE #jobs(
job varchar(30),
skill int)      
     
INSERT INTO #names
SELECT 'name1', 1 UNION ALL
SELECT 'name2', 1 UNION ALL
SELECT 'name2', 2 UNION ALL
SELECT 'name2', 4 UNION ALL
SELECT 'name2', 5 UNION ALL
SELECT 'name3', 2
     
INSERT INTO #jobs
SELECT 'job1', 1 UNION ALL
SELECT 'job2', 1 UNION ALL
SELECT 'job2', 2 UNION ALL
SELECT 'job3', 2 UNION ALL
SELECT 'job4', 3 UNION ALL
SELECT 'job5', 2 UNION ALL
SELECT 'job5', 1 UNION ALL
SELECT 'job5', 4
     
;with names as (
select distinct t1.name,rtrim(substring(isnull((select ','+convert(varchar,t2.skill) from #names t2 where t1.name = t2.name for xml path('')),' '),2,2000)) skill
 from #names t1)
 ,jobs as (
select distinct t1.job,rtrim(substring(isnull((select ','+convert(varchar,t2.skill) from #jobs t2 where t1.job = t2.job for xml path('')),' '),2,2000)) skill
 from #jobs t1)
select n.name,j.job
   from names n
   join jobs j on n.skill like '%'+j.skill+'%'

DROP TABLE #names
DROP TABLE #jobs
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Author Comment

by:rlarian
ID: 39752914
Dale, just noticed i had two different solutions... checking yours
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Expert Comment

by:Dale Burrell
ID: 39752918
You're doing it quite different from what I suggested. You're building a string of concatenated skills per person and per job and then trying to match them. Of course order matters then because if you look at the intermediate results (below) the name has a computed string '1,2,4' but the job has '2,1,4'. You can solve that by ordering the query where you compute the string e.g. #names t2 where t1.name = t2.name order by Skill for xml path" but you've over-complicated it for my liking.

name1      1      job1      1
name1      1      job2      1,2
name1      1      job3      2
name1      1      job4      3
name1      1      job5      2,1,4
name2      1,2,4,5      job1      1
name2      1,2,4,5      job2      1,2
name2      1,2,4,5      job3      2
name2      1,2,4,5      job4      3
name2      1,2,4,5      job5      2,1,4
name3      2      job1      1
name3      2      job2      1,2
name3      2      job3      2
name3      2      job4      3
name3      2      job5      2,1,4
0
 
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Author Closing Comment

by:rlarian
ID: 39752927
Dale, there are actually 5 tables. person, personSkillMap, skill, jobSkillMap, job

job can can have many skills and a person must have all the skills to match the job.

yours is doing what i need to get me in the right direction. thanks for the help.
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LVL 4

Author Comment

by:rlarian
ID: 39752989
Dale, thanks again. here is my 5 table version.

declare @Name table (ID int, Name varchar(30), NameSkillMap int)
declare @Job table (ID int, Job varchar(30), JobSkillMap int)
declare @Skill table (ID int, Skill varchar(30))
declare @NameSkillMap table (NameID int, SkillID int)
declare @JobSkillMap table (JobID int, SkillID int)

insert into @Name (ID, Name, NameSkillMap)
 select 1, 'name1', 1 UNION ALL
 select 2, 'name2', 2 UNION ALL
 select 3, 'name3', 3 UNION ALL
 select 4, 'name4', 4
     
insert into @Job (ID, Job, JobSkillMap)
 select 1, 'job1', 1 UNION ALL
 select 2, 'job2', 2 UNION ALL
 select 3, 'job3', 3 UNION ALL
 select 4, 'job4', 4
 
insert into @Skill (ID,Skill)
 select 1, 'skill1' UNION ALL
 select 2, 'skill2' UNION ALL
 select 3, 'skill3' UNION ALL
 select 4, 'skill4'
 
insert into @NameSkillMap (NameID, SkillID)
 select 1, 1 UNION ALL
 select 2, 2 UNION ALL
 select 3, 1 UNION ALL
 select 3, 2 UNION ALL
 select 3, 3 UNION ALL
 select 3, 4 UNION ALL
 select 4, 1 UNION ALL
 select 4, 4
 
insert into @JobSkillMap (JobID, SkillID)
 select 1, 1 UNION ALL
 select 1, 2 UNION ALL
 select 2, 1 UNION ALL
 select 2, 2 UNION ALL
 select 2, 3 UNION ALL
 select 2, 4 UNION ALL
 select 3, 2 UNION ALL
 select 4, 4

select n.Name, j.Job
from @Job J, @Name N
where not exists (
  select 1
  from @Job J1
   join @JobSkillMap JSM on JSM.JobID = J1.ID
   join @Skill SJ on SJ.ID = JSM.SkillID
  where J1.Job = J.Job
  and not exists (select 1 from @Name N1
                                          join @NameSkillMap NSM on NSM.NameID = N1.ID
                                          join @Skill S on S.ID = NSM.SkillID
                                          where N1.Name = N.Name and S.Skill = SJ.Skill)
)
order by N.Name, J.Job
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Expert Comment

by:Dale Burrell
ID: 39752996
Nice one - thats more what I expected - its working I assume?
0
 
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Author Comment

by:rlarian
ID: 39753067
working like a champ. thanks for the help.
0
 
LVL 40

Expert Comment

by:Sharath
ID: 39755167
I have tried grouping all skills as a set with XML. An "ORDER BY" is needed for XML solution to work.
But I think Dale has nailed it with simple and elegant approach. Nice work Dale.
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