Question

I have an intermediate table which looks something like this (after I join 2 other tables) :

    ID       Meta_key   Meta_value
    

    22     Company   Amazon

    22     Address   Seattle


    25     Company   Google

    25     Address   Mountain View

    

And so on…

My question is what’s the easiest way to write a single query to get BOTH the company name and address for a given ID? What’s the best way to structure this where clause since I would want something like select meta_value from table where meta_key = “Company” and meta_key = “Address” (that obviously wont work)…I’m sure there is a simple way to do this but can’t seem to think of it right now, I’ll also need aliases to distinguish between the meta_value for company and address in the result set.

Thanks in advance

Answer 1

If you want both keys in same row you could self-join the table

SELECT t1.ID, t1.Meta_value as "Company", t2.Meta_value as "Address"
FROM table t1
JOIN table t2 ON t2.ID = t1.ID AND t2.Meta_key = "Address"
WHERE t1.Meta_key = 'Company'

Or if you want single ID even simpler with subquery:

SELECT 
    22 as "ID",
    (SELECT Meta_value FROM table WHERE id = 22 AND Meta_key = "Company") as "Company",    
    (SELECT Meta_value FROM table WHERE id = 22 AND Meta_key = "Address") as "Address";