根据 table3 中的条件从 table2 插入 table1

Question

Hello i have some problem with this:

I have 3 tables

Table users :

username	tele	notify
user1	555-123456	true
user2	555-000123	false
user3	null	false

Table datesTimes

date	userame
2021-10-10	user1
2021-10-10	user2
...	...

Table out_notifications

telephone	message

Now what i want insert data into table out_notifications from table datesTimes only for users which have telephone number and notification turned on.

So i have constructed following query:

INSERT INTO out_notifications (telephone,message)
SELECT (select tele from users where users.username = datesTimes.username),
       'some message'    --(generated by system)
FROM datesTimes
WHERE date = '2021-10-10';

Now where place a subquery which select only users with tel. number and notifications turned on ?

Used db PostgreSQL

Thanks for any help.

Answer 1

use a join instead of a subselect.

INSERT INTO out_notifications (telephone,message)
  SELECT users.tele,
     'some message'    --(generated by system)
  FROM users 
  JOIN datesTimes
      ON users.username = datesTimes.username,
  WHERE datesTimes.date = '2021-10-10'
    AND users.tele <> ''
    AND users.notify;