Hi i have queries that I use to get single result. How could I do this with just one query?
First I ask
SELECT "userId" FROM "Devices" WHERE "deviceNumber" = '0001563055080020'
Then save UserId and ask following another table
SELECT "email" FROM "Users" WHERE "id" = '1'
Any ideas?
NESTED QUERY
SELECT "email"
FROM "Users"
WHERE "id" IN (
SELECT "userId"
FROM "Devices"
WHERE "deviceNumber" = '0001563055080020')
INNER JOIN
select u.email
from users u, devices d
where d.userid = u.id
and d.deviceNumber = '0001563055080020'
this is called a join
here is one syntax
select email
from users u, devices d
where d.userid = u.id
I recommend using the new join syntax. I think it's cleaner and easier to read. One can immediatly see there's an inner join. Furthermore the where-clause can be used just for filtering.
select u.*
from users u
inner join devices d on u.id=d.user_id
where d.device_number='0001234';
INNER JOIN.