如何在 mysql/mariadb 中查询与 id 相同的多行

Question

i'm stuck and trying to figure out how to do the right WHERE query. This is the table:

post_id   property_id   property_value_id   property_value_custom   
77        2             3                   NULL
79        1             1                   NULL
79        2             2                   NULL
79        2             3                   NULL
79        4             NULL                111
80        3             4                   NULL 

I want to select the post, WHERE property_value_id = 3 AND property_value_custom = "111" .

The result should be post_id 79. How to query that?

Answer 1

You can group by post_id and set the condition in the HAVING clause:

select post_id
from tablename
group by post_id
having sum(property_value_id = 3) > 0 
   and sum(property_value_custom = 111) > 0

or:

having max(property_value_id = 3) = 1 
   and max(property_value_custom = 111) = 1