Question

I have 3 tables:

1. districts | id, zipcode, district
2. subscription | id, userid, status, level
3. profile | id, userid, zip

I am trying to count the amount of zip codes from active subscriptions and group them by district. ( I am using LEFT() so I can can include zips in the #####-#### format). The query works in 6.4 seconds locally, but on the server isn’t outputting in a timely manner. What can I do to speed this up?

I have written:

SELECT COUNT( d.zipcode ) total, d.district
FROM districts AS d
JOIN profile AS p ON d.zipcode = LEFT(p.zip, 5)
JOIN subscriptions AS s ON s.userid = p.userid
WHERE s.status = 1
GROUP BY d.district

Thanks!

Answer 1

create an index on:
d.zipcode
p.zip
s.userid
p.userid
s.status