SQL 选择具有特定值的不同 ID

Question

Could you tell me please how to find users with FormFieldID ((1 AND 2) OR 3), so the SQL query should return UserIDs: 7, 8, 9.

The table:

I use SQL Server.

Thank you!

Answer 1

I would recommend aggregation and having clause to implement the filtering logc:

select userid
from mytable
group by userid
having 
    (
         max(case when formfieldid = 1 then 1 end) = 1 
         and max(case when formfieldid = 2 then 1 end) = 1
    )
    or max(case when formfieldid = 3 then 1 end) = 1

Depending on your actual database, which you did not tell, there may be neater options to express the conditions. For example, in MySQL:

having 
    (max(formfieldid = 1) and max(formfieldid = 2))
    or max(formfieldid = 3)