Question

Supposing I have a MySQL table (meta_table) as follows with the following data:

meta_id,post_id,meta_key,meta_value
5,10,my_key1,value1
10,11,my_key2,value2
15,12,my_key3,value3
35,11,my_key4,value4

How can I get the post_id if meta_value is value2 and value4 (the answer should be 11).
I have tried this:

SELECT post_id from meta_table where meta_value='value2' and meta_value='value4' 

But it does not return 11 as the post_id. Any suggestions?

Answer 1

With a join:

SELECT a.post_id
FROM meta_table AS a
JOIN meta_table AS b ON a.post_id = b.post_id
WHERE a.meta_value = 'value2' AND b.meta_value = 'value4'

http://www.sqlfiddle.com/#!2/96d2b/4/0