Question

I have a Skills table which has 14 records in it. It is structured like this:
| id | name |

I then have a User_Skills table which I want to join to the skills table.
Here’s is structure:
| User_id | Skill_id |

Basically I want to be able to do a join which always results in 14 records and shows NULL in any fields the user isn’t associated with.

I almost got the result I want with this query
Code:

SELECT * FROM Skills LEFT JOIN User_Skills ON Skills.id = User_Skills.Skill_id

Edit: To make it clearer – this is the set of results with this query. I need to select the skill by the User_id, but still show all 14 skills even if the result is Null in the User_id field.

id  name    User_id     Skill_id
1   HGV1    1000    1
1   HGV1    1001    1
2   HGV2    1001    2
3   No.1 Mechanic   1000    3
3   No.1 Mechanic   1001    3
4   No.2 Mechanic   1001    4
5   Designer    1001    5
5   Designer    1000    5
6   Engineer    1000    6
7   Data Analysis   1001    7
7   Data Analysis   1000    7
8   Coaching/Inst.  1001    8
8   Coaching/Inst.  1000    8
9   Hospitality     1000    9
10  Promo Girl  1000    10
11  Public Relations    NULL    NULL
12  Photographer    NULL    NULL
13  Film Crew   1001    13
14  Physiotherapist     NULL    NULL

but it displays the amount of records I have in the user_skills table… ie, duplicate skill names because more than one user is associated with the skill.

This too, almost gets it:
Code:

SELECT * FROM Skills LEFT JOIN User_Skills ON Skills.id = User_Skills.Skill_id WHERE User_id = 1001

but this shows only the skills the user is associated with and doesn’t show any NULL entries like I want.

Does anyone know how I can achieve this query?

Answer 1

SELECT * FROM 
Skills LEFT OUTER JOIN 
(select distinct user_id, skill_id from User_Skills where user_id = 1001) xxx
    ON Skills.id = xxx.Skill_id 

does that produce what you need?