如何从左表返回行，其中右表的条件在没有子查询的所有行上为真

Question

I have 2 table with this sample data.

Parent

id	title
1	A
2	B
3	C

Childs

id	p_id	number
1	1	1
2	1	2
3	1	3
4	2	4
5	2	5
6	2	6
7	3	2
8	3	7
9	3	8
10	3	9

And I want to get rows from parents join with childs and number > 3.

But I want to receive only parent whose condition is correct on all childs, and even if the condition is not correct on one child, the parent should not be returned

And I want to do without subquery

SELECT * FROM `parent` 
LEFT JOIN `childs` on `childs`.`p_id` = `parent`.`id` 
WHERE `childs`.`number` > '3'

I want to get only parent B with this condition.

Thanks.

Answer 1

Maybe something like this can work

SELECT *
FROM parent p, child c2
WHERE EXISTS ( SELECT * 
          FROM child c1 
          WHERE p.id = c1.p_id AND c1.number >3)  AND  p.id = c2.p_id AND c2.number <=3

Answer 2

Try this:

SELECT p.id, p.title, GROUP_CONCAT(number ORDER BY number) val
  FROM Parent p JOIN Childs c ON p.id=c.p_id
  GROUP BY p.id, p.title
  HAVING SUBSTRING_INDEX(val,',',1) > 3;

Here's a fiddle demo

Answer 3

And I want to get rows from parents join with childs and number > 3.

But I want to receive only parent whose condition is correct on all childs, and even if the condition is not correct on one child, the parent should not be returned

I would recommend:

SELECT p.id, p.title
FROM Parent p JOIN
     Childs c
     ON p.id = c.p_id
GROUP BY p.id, p.title
HAVING MIN(number) > 3;

There is no reason at all to use strings for what you want to do. It just confuses the logic.

An even more efficient method would use NOT EXISTS :

select p.*
from p
where not exists (select 1
                  from childs c
                  where p.id = c.p_id and c.number <= 3
                 );