Slow mysql query with multiple joins - mysql

Question

I have the following tables in my database:
product_fav:
CREATE TABLE `product_fav` (
`user_id` int(9) unsigned NOT NULL,
`asin` varchar(10) NOT NULL DEFAULT '',
`date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
`price` decimal(7,2) NOT NULL,
PRIMARY KEY (`user_id`,`asin`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
product_info:
CREATE TABLE `product_info` (
`asin` varchar(10) NOT NULL,
`name` varchar(200) DEFAULT NULL,
`brand` varchar(50) DEFAULT NULL,
`part_number` varchar(50) DEFAULT NULL,
`url` text,
`image` text,
`availabillity` tinyint(1) NOT NULL DEFAULT '1',
PRIMARY KEY (`asin`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
product_price:
CREATE TABLE `product_price` (
`asin` varchar(10) NOT NULL,
`date` date NOT NULL,
`timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`price` decimal(7,2) NOT NULL DEFAULT '0.00',
PRIMARY KEY (`asin`,`date`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
I have the following query:
SELECT pi.*,
pp.price,
pf.date,
pf.price AS price_added,
round((100.0 (pp.price - pf.price) / pf.price),0) AS percentdiff
FROM product_info pi
JOIN
(
SELECT *
FROM product_price
ORDER BY date DESC) pp
ON pp.asin = pi.asin
JOIN product_fav pf
ON pp.asin = pf.asin
WHERE pf.user_id=". $user['user_id'] ."
GROUP BY asin
Product price has many records and query needs about 3 second. Is it possible to make it faster?
I have also the same issue with search query:
SELECT pi.*,
price,
date
FROM product_info pi
JOIN (SELECT *
FROM product_price
ORDER BY date DESC) pp
ON pi.asin = pp.asin
WHERE ( ` NAME ` LIKE '%".$search."%' )
GROUP BY pi.asin
ORDER BY price
EXPLAIN return this:
+----+-------------+---------------+--------+---------------+---------+---------+---------------+--------+---------------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+---------------+--------+---------------+---------+---------+---------------+--------+---------------------------------+
| 1 | PRIMARY | <derived2> | ALL | NULL | NULL | NULL | NULL | 106709 | Using temporary; Using filesort |
| 1 | PRIMARY | pi | eq_ref | PRIMARY | PRIMARY | 32 | pp.asin | 1 | |
| 1 | PRIMARY | pf | eq_ref | PRIMARY | PRIMARY | 36 | const,pp.asin | 1 | |
| 2 | DERIVED | product_price | ALL | NULL | NULL | NULL | NULL | 112041 | Using filesort |
+----+-------------+---------------+--------+---------------+---------+---------+---------------+--------+---------------------------------+

Answer 1

You dont ORDER before JOIN, If you need order do it after the WHERE and GROUP BY so less data to sort.
JOIN
(
SELECT *
FROM product_price
ORDER BY date DESC) pp
Create index for asin so JOIN for ON pp.asin = pi.asin will be more efficient
Create index for user_id so the WHERE pf.user_id=". $user['user_id'] ." will be more efficient

Answer 2

Try running an EXPLAIN on your query to figure out where the bottle-neck is.
What's with the ORDER BY date in the inner query? Try getting rid of it. Also try replacing the inner query with a JOIN, they tend to be faster.
Also, do you have an index on the date field? Try adding one for the ORDER BY at the end of the query.