exlusion

[countdrac]

hi

im trying to get all the userId's that have been inactive in the last 30 days...

so far i have

 

SELECT userid FROM users (all the users)

 

and i have

 

SELECT userid FROM transactions

WHERE DATE_SUB(CURDATE(), INTERVAL 28 DAY) <= EndAt

 

so i need to exclude the second query from the first... how do i do that and just end up with the userid's of those not been used in the last 28 days (EndAt is a list of all transaction dates)

 

thanks

[Mchl]

SELECT u.userid
FROM users AS u
LEFT JOIN
(SELECT userid FROM transactions
   WHERE DATE_SUB(CURDATE(), INTERVAL 28 DAY) <= EndAt) AS t
USING (userid)
WHERE t.userid IS NULL

[countdrac]

Thanks for the answer

 

if you have the time could you please explain to me where/how the exclusion takes place.

i really need to learn this stuff... not just copy and paste...

 

thanks again

[Mchl]

Remove WHERE t.userid IS NULL from this query and see results. This should make it a bit clearer for you.