CODEWITHSUNDEEP
mysql
Jeebsion
Jeebsion

Reputation: 353

How can I improve nested mysql query speed such as this one?

I'm having a bit of difficulty retrieving fast responds from the mysql server whilst performing such query:

select distinct(products.id) as product_id,products.title as product_name, (select count(id) from stock where stock.available='0' and stock.product_id=products.id) as none,
(select count(id) from stock where stock.available='1' and stock.product_id=products.id) as available,
(select count(id) from stock where stock.available='2' and stock.product_id=products.id) as staged,
(select count(id) from stock where stock.available='3' and stock.product_id=products.id) as departed,
(select count(id) from stock where stock.available='4' and stock.product_id=products.id) as delivered
from products,stock where products.id=stock.product_id;

I wonder if there's any other query method that will deliver much faster respond. Thanx :-)

Upvotes: 1

Views: 50

Answers (1)

Hamlet Hakobyan
Hamlet Hakobyan

Reputation: 33381

Something like this:

SELECT
  P.id as product_id,
  P.title as product_name,
  SUM(CASE WHEN S.available = 0 THEN 1 ELSE 0 END) as none,
  SUM(CASE WHEN S.available = 1 THEN 1 ELSE 0 END) as available,
  SUM(CASE WHEN S.available = 2 THEN 1 ELSE 0 END) as staged,
  SUM(CASE WHEN S.available = 3 THEN 1 ELSE 0 END) as departed,
  SUM(CASE WHEN S.available = 4 THEN 1 ELSE 0 END) as delivered 
FROM products P
      JOIN stock S
          ON P.id = S.product_id
    GROUP BY P.id,
             P.title

Upvotes: 3

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