MySQL left the outer join slow

Question

Hoping to get some help on this, I worked on this for a while and cannot get it faster:

SELECT date, count(id) as 'visits' FROM dates 
LEFT OUTER JOIN visits 
ON (dates.date = DATE(visits.start) and account_id = 40 ) 
WHERE date >= '2010-12-13' AND date <= '2011-1-13' 
GROUP BY date ORDER BY date ASC

This request takes about 8 seconds. I added indexes to date.date, visits .start, visits .account_id and visits .start + visits .account_id and cannot make it work faster.

Table structure (only displaying the corresponding columns in the visit table):

create table visits (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `account_id` int(11) NOT NULL,
    `start` DATETIME NOT NULL,
    `end` DATETIME NULL,
    PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

CREATE TABLE `dates` (
  `date` date NOT NULL,
  PRIMARY KEY (`date`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

The date table contains all days from 2010-1-1 to 2020-1-1 (~ 3k rows). The visit table contains about 400 thousand rows, dated 2010-6-1 until yesterday. I use a date table, so the connection will return 0 visits for several days when there were no visits.

Results I want to find:

+------------+--------+
| date       | visits |
+------------+--------+
| 2010-12-13 |    301 |
| 2010-12-14 |    356 |
| 2010-12-15 |    423 |
| 2010-12-16 |    332 |
| 2010-12-17 |    346 |
| 2010-12-18 |    226 |
| 2010-12-19 |    213 |
| 2010-12-20 |    311 |
| 2010-12-21 |    273 |
| 2010-12-22 |    286 |
| 2010-12-23 |    241 |
| 2010-12-24 |    149 |
| 2010-12-25 |    102 |
| 2010-12-26 |    174 |
| 2010-12-27 |    258 |
| 2010-12-28 |    348 |
| 2010-12-29 |    392 |
| 2010-12-30 |    395 |
| 2010-12-31 |    278 |
| 2011-01-01 |    241 |
| 2011-01-02 |    295 |
| 2011-01-03 |    369 |
| 2011-01-04 |    438 |
| 2011-01-05 |    393 |
| 2011-01-06 |    368 |
| 2011-01-07 |    435 |
| 2011-01-08 |    313 |
| 2011-01-09 |    250 |
| 2011-01-10 |    345 |
| 2011-01-11 |    387 |
| 2011-01-12 |      0 |
| 2011-01-13 |      0 |
+------------+--------+

Thanks in advance for your help!

Answer 1

:

ON (dates.date = DATE(visits.start) and account_id = 40 ) 

DATE visits.start, MySQL .

, start_date end_date dates . , 2011-01-01 2011-01-01 00:00:00, 2011-01-01 23:59:59.

:

SELECT date, count(id) as 'visits' FROM dates 
LEFT OUTER JOIN visits 
ON (visits.start BETWEEN dates.start_date AND dates.end_date and account_id = 40 ) 
WHERE date >= '2010-12-13' AND date <= '2011-1-13' 
GROUP BY date ORDER BY date ASC

.

Answer 2

, - DATE(). Visites, , . MySQL , .

Answer 3

How about something like this: an outer join as a result of choosing from eumiro?

SELECT date, v.visits as 'visits' FROM dates 
LEFT OUTER JOIN (SELECT DATE(start) as dt, count(id) as 'visits'
FROM visits 
WHERE account_id = 40
AND date BETWEEN '2010-12-13' AND '2011-01-13' 
GROUP BY DATE(start)
ORDER BY 1)
v
ON (dates.date = v.dt ) 
WHERE date >= '2010-12-13' AND date <= '2011-1-13' 

Edit: edited SQL Edit: another option is the built-in selection, something like this:

SELECT date, (select count(*)  as 'visits' 
FROM  from visits 
where date = DATE(visits.start) and account_id = 40 ) 
) from dates
WHERE date >= '2010-12-13' AND date <= '2011-1-13' 
ORDER BY date ASC