需要优化 SQL 查询

Question

Now i have this query

SELECT 
  d.domain,
  r.domain_id,
  r.d_lider, 
  u.email,
  u.f_name,
  u.l_name,
  u.role 
FROM (
    SELECT r.domain_id, 
    count(r.id) AS d_lider 
    FROM bxa_request AS r
    WHERE MONTH(r.created) = MONTH(CURRENT_DATE()) 
    AND YEAR(r.created) = YEAR(CURRENT_DATE())
    GROUP BY r.domain_id
    ORDER BY d_lider
) AS r
LEFT JOIN bxa_user AS u
ON (
    u.domain_id = r.domain_id 
    AND (u.role = 'A' OR u.role = 'E')
)
LEFT JOIN bxa_domain AS d 
ON (r.domain_id = d.id )
WHERE r.d_lider = (
    SELECT count(*) AS max 
    FROM bxa_request AS r  
    WHERE MONTH(r.created) = MONTH(CURRENT_DATE()) 
    AND YEAR(r.created) = YEAR(CURRENT_DATE())
    GROUP BY r.domain_id 
    ORDER BY max DESC LIMIT 1
)
ORDER BY r.d_lider DESC

But if i will check this query with EXPLAIN command i see what query is not optimizely. Please help me optimize my query http://joxi.ru/DmBEd5puNoVJBr?d=1

I want exclude big count operation from my query, may be join or anything

Answer 1

WHERE MONTH(r.created) = MONTH(CURRENT_DATE()) 
  AND YEAR( r.created) = YEAR( CURRENT_DATE())

-->

WHERE r.created >= CURDATE() - INTERVAL DAYOFMONTH(CURDATE)-1 DAY
  AND r.created <  CURDATE() - INTERVAL DAYOFMONTH(CURDATE)-1 DAY + 1 MONTH

That would give an index a chance of being used.

INDEX(created, domain_id) may help.

ORDER BY d_lider in the derived table is ignored.

Please put things that show how tables are related in ON ; put the rest in WHERE .

If LEFT is not needed, use INNER ; it could help with optimization.

Please avoid using r as the alias for both the outer query and a subquery -- it makes it difficult for humans to parse.

Where possible, turn subqueries into JOINs .

To discuss further, update the Question with whatever changes make sense, and please provide SHOW CREATE TABLE .