Question

I am using the below SQL query but it takes more than 180 sec to execute. Is there a way to speed it up ? This SQL give me the pic_id and of all the females.

SELECT pic_id, small
FROM picture
WHERE hide =0
AND userhide =0
AND  `fbid` 
IN (

      SELECT fbid
      FROM user
      WHERE gender =  "female"
   )

ORDER BY  `picture`.`pic_id` ASC 
LIMIT 1500 , 200

The Explain SQL

id select_type         table    type   possible_keys  key      key_len  ref   rows  Extra
1  PRIMARY             picture  index  NULL           PRIMARY  4        NULL  1700  Using where
2  DEPENDENT SUBQUERY  user     ALL    NULL           NULL     NULL     NULL  7496  Using where

— Result of explain statement for Tim’s sql answer —

id  select_type table   type    possible_keys   key key_len ref rows    Extra
1   SIMPLE  picture ALL NULL    NULL    NULL    NULL    41443   Using where; Using temporary; Using filesort
1   SIMPLE  user    ALL NULL    NULL    NULL    NULL    7501    Using where; Using join buffer

— Structure —

CREATE TABLE `user` (
`sid` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) CHARACTER SET utf8 NOT NULL,
`first_name` varchar(255) CHARACTER SET utf8 NOT NULL,
`username` varchar(255) CHARACTER SET utf8 NOT NULL,
`birthday` date NOT NULL,
`location` varchar(255) CHARACTER SET utf8 NOT NULL,
`gender` varchar(6) CHARACTER SET utf8 NOT NULL,
`created` date NOT NULL,
`fbid` bigint(50) NOT NULL,
`token` varchar(255) CHARACTER SET utf8 NOT NULL,
`relationship_status` varchar(20) CHARACTER SET utf8 NOT NULL,
`smallest` varchar(255) CHARACTER SET utf8 NOT NULL,
`email` varchar(40) CHARACTER SET utf8 NOT NULL,
`ref` varchar(15) NOT NULL,
PRIMARY KEY (`sid`),
KEY `gender` (`gender`),
KEY `fbid` (`fbid`)
) ENGINE=MyISAM AUTO_INCREMENT=7595 DEFAULT CHARSET=latin

—- structure of picture table —

CREATE TABLE `picture` (
 `fbid` bigint(50) NOT NULL,
 `pic_id` int(11) NOT NULL AUTO_INCREMENT,
 `pic_location` varchar(255) NOT NULL,
 `hide` int(1) NOT NULL,
 `small` varchar(255) NOT NULL,
 `userhide` int(1) NOT NULL,
 `likes` int(10) NOT NULL,
 `hot` int(1) NOT NULL,
 PRIMARY KEY (`pic_id`),
 UNIQUE KEY `pic_location` (`pic_location`),
 UNIQUE KEY `small` (`small`),
 KEY `fbid` (`fbid`),
 KEY `hide` (`hide`),
 KEY `userhide` (`userhide`)
) ENGINE=MyISAM AUTO_INCREMENT=42749 DEFAULT CHARSET=latin1

Answer 1

try something like this:

SELECT pic_id, small
FROM picture
INNER JOIN user ON ( picture.fbid = user.fbid and user.gender='female' )
WHERE hide =0
AND userhide =0
ORDER BY  `picture`.`pic_id` ASC 
LIMIT 1500 , 200

I put gender in the join because a query will not return rows that don’t have a match on an inner join.

You should also read this stack overflow topic

EDIT:

make sure you have indexed the following fields:

picture.fbid
user.fbid
user.gender
picture.hide
picture.userhide