CODEWITHSUNDEEP
sqlpostgresqlsqlalchemy
Anton Trishenkov
Anton Trishenkov

Reputation: 125

SQL check if multiple exists

I have a table Users looks like this:

ID    COMPANY_ID    FIRST_NAME

1     1             John
2     1             Mary
3     2             Ivan
4     1             Arnold
5     3             Sam

I need SQL query that may check that pairs exists for user_id, company_id of one company and return [[id, true], [id, false].

It mean I want ask if users [1, 4, 7, 17] of company 2 exists and receive [[1, true], [4, true], [7, false], [17, true]].

It would be a great if you may suggest how do this with sqlalchemy Core.

Upvotes: 2

Views: 1574

Answers (1)

Gordon Linoff
Gordon Linoff

Reputation: 1270503

In SQL, you would use left join. Assuming Users has not duplicates, you would do something like:

select t.id, (case when u.id is null then 0 else 1 end) as flag
from (select 1 as id union all
      select 4 union all
      select 7 union all
      select 17
     ) t left join
     users u
     on u.id = t.id and u.company = 2;

Upvotes: 1

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