MySQL Join Same Table

Question

I have the table \'meta_data\' with the following fields:

• id
• post_id
• meta_key
• meta_value

I\'d like to loop throug

Answer 1

To achieve this you should use the LEFT OUTER JOIN operation joining the same table.

SELECT a.*
FROM meta_data a
LEFT OUTER JOIN meta_data b ON a.post_id = b.post_id AND b.meta_value = 'def'
WHERE 
a.meta_value = 'abc'
AND b.post_id IS null