How to SELECT FROM the intersection of multiple subquery results? - mysql

Question

First of all, good news: I have only 1 table.
Now, I have 3 similar queries:
SELECT id FROM (
SELECT * FROM my_table
ORDER BY columnA
DESC LIMIT 600
) AS aliasA
WHERE (revenue > 10000);
SELECT id FROM (
SELECT * FROM my_table
ORDER BY columnB
DESC LIMIT 400, 999999999999
) AS aliasB
WHERE (revenue > 10000);
SELECT id FROM (
SELECT * FROM my_table
ORDER BY columnC
DESC LIMIT 800;
) AS aliasC
WHERE (revenue > 10000);
Notice the WHERE clause are the same.
Is there a way to combine these 3 queries so that I can search from the intersection of the 3 sub-queries (find rows that match all 3 sub-queries, and also my WHERE clause)?
By the way, if my single queries (before combining) can be simplified, please let me know.
Thanks!

Answer 1

SELECT ID FROM
(SELECT id FROM (
SELECT *
FROM my_table
WHERE (revenue > 10000)
ORDER BY columnA DESC
LIMIT 600
) AS aliasA) AS a
INNER JOIN (
SELECT id FROM (
SELECT *
FROM my_table
WHERE (revenue > 10000)
ORDER BY columnB DESC
LIMIT 400, 999999999999
) AS aliasB
)
AS b ON a.id = b.id
INNER JOIN (
SELECT id FROM (
SELECT *
FROM my_table
WHERE (revenue > 10000)
ORDER BY columnC DESC
LIMIT 800
) AS aliasC
)
AS c ON a.id = c.id AND b.id = c.id
then you can search this query

Answer 2

In your case, the best solution will be JOIN USING (id):
SELECT id
FROM (SELECT id FROM my_table ORDER BY columnA DESC LIMIT 600)
aliasA
JOIN (SELECT id FROM my_table ORDER BY columnB DESC LIMIT 400, 999999999999)
aliasB USING (id)
JOIN (SELECT id FROM my_table ORDER BY columnC DESC LIMIT 800)
aliasC USING (id)
JOIN my_table USING (id)
WHERE (revenue > 10000);
If you didn't have LIMIT in your subquery, you could have used id IN:
SELECT id FROM my_table
WHERE (
id IN (SELECT id FROM my_table ORDER BY columnA DESC LIMIT 600)
AND
id IN (SELECT id FROM my_table ORDER BY columnB DESC LIMIT 400, 999999999999)
AND
id IN (SELECT id FROM my_table ORDER BY columnC DESC LIMIT 800)
AND
revenue > 10000
)
However LIMIT is not supported in subquery, so you can't do it.
If you were using other SQLs, you could have used INTERSECT:
(SELECT id FROM my_table ORDER BY columnA DESC LIMIT 600)
INTERSECT
(SELECT id FROM my_table ORDER BY columnB DESC LIMIT 400, 999999999999)
INTERSECT
(SELECT id FROM my_table ORDER BY columnC DESC LIMIT 800)
INTERSECT
(SELECT id FROM my_table WHERE revenue > 10000)
However MySql doesn't support INTERSECT.

Answer 3

You can use INNER JOIN on key: id then put where clause at the end. All 3 queries is making use of revenue > 10000 and it can be combined in onenwhere clause since all revenue columnn comes from the same table.
select t1.id from (
SELECT id, revenue FROM (
SELECT * FROM my_table
ORDER BY columnA
DESC LIMIT 600
) AS aliasA) as t1
INNER JOIN (
SELECT id FROM (
SELECT * FROM my_table
ORDER BY columnB
DESC LIMIT 400, 999999999999
) AS aliasB) as t2 on t1.id= t2.id
INNER JOIN (
SELECT id, revenue FROM (
SELECT * FROM my_table
ORDER BY columnC
DESC LIMIT 800;
) AS aliasC) as t3 on t1.id =t3.id
WHERE (t1.revenue > 10000);