CODEWITHSUNDEEP
postgresql
sylargaf
sylargaf

Reputation: 532

Postgres Retrieve Values Conditionally?

not sure if my title is exactly waht I want to accomplish but it was a guess. I'm trying to see if something like the following is possible in PGSQL.

Basically, I have a set of data that I want to pull no matter what. But, if certain columns of data arent null, then I want it to join another table and pull data referencing that data. So, for example, let's say I have data like:

User_Accounts:

userid companyname first name
25df Test Company 1 Bob
921f Test Company 1 Lawrence
882s Company test 2 NULL
8234 Test Company 1 Cleo
8244s Company test 2 Paul
825q Test Company 1 Bruce
5552 B Alpha Company Lenny

Baseball_Rosters:

userid baseball_team company position
25df Atlanta Aliens Test Company 1 P
882s Boston Bruisers Company test 2 DH
8234 California Craisins Test Company 1 1B
8244s Tampa Titans Company test 2 P
null Tampa Titans Test Company 1 P
5552 Tampa Titans B Alpha Company 2B
5552 Tampa Titans B Alpha Company SS
921f California Craisins Test Company 1 P
825q Boston Bruisers Test Company 1 P

How would I perform a query to get a result like:

userid baseball_team company first name position
null Tampa Titans Test Company 1 null P
25df Atlanta Aliens Test Company 1 Bob P
825q Boston Bruisers Test Company 1 Bruce P
921f California Craisins Test Company 1 Lawrence P

So essentially, inserting the firstname & lastname field if and only if userid is not null? And then to order by userid null first and then in order? Thanks for the help.

Upvotes: 0

Views: 109

Answers (1)

Alan Ainsworth
Alan Ainsworth

Reputation: 78

This looks like a LEFT OUTER JOIN.

Like this:

SELECT baseball_rosters.user_id, baseball_team, comapny, first_name, position
FROM baseball_rosters
LEFT OUTER JOIN user_accounts ON user_accounts.user_id = baseball_rosters.user_id;

Upvotes: 1

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