How to merge results of two mysql tables in one output - mysql

Question

I have two similar mysql tables and want to get the data from both of them in one output (merge). How can I do it?
For this reason I have created two separate queries to check that I get what I'm looking for.
First: Table -> web_session
SELECT date_format(booking_time, '%m-%Y') AS m, count(booking_time) AS b
FROM web_session
WHERE
date(booking_time) >= date_sub(curdate(), interval 12 month)
AND
date(booking_time) <= date_add(curdate(), interval 6 month)
GROUP BY month(booking_time)
ORDER BY booking_time ASC;
Output:
m, b
10-2013, 15
11-2013, 6
12-2013, 13
01-2014, 10
02-2014, 10
03-2014, 25
04-2014, 1
Second: Table -> web_log
SELECT date_format(request_time, '%m-%Y') AS m, count(request_time) AS r
FROM web_log
WHERE
date(request_time) >= date_sub(curdate(), interval 12 month)
AND
date(request_time) <= date_add(curdate(), interval 6 month)
GROUP BY month(request_time)
ORDER BY request_time ASC;
Output:
m, r
03-2014, 45
04-2014, 35
desired output:
m, b, r
10-2013, 15, null
11-2013, 6, null
12-2013, 13, null
01-2014, 10, null
02-2014, 10, null
03-2014, 25, 45
04-2014, 1, 35

Answer 1

You need to join them. Try this:
SELECT T1.m,T1.b,T2.r FROM
(
SELECT date_format(booking_time, '%m-%Y') AS m, count(booking_time) AS b
FROM web_session
WHERE
date(booking_time) >= date_sub(curdate(), interval 12 month)
AND
date(booking_time) <= date_add(curdate(), interval 6 month)
GROUP BY month(booking_time)
ORDER BY booking_time ASC;) T1
LEFT OUTER JOIN
(SELECT date_format(request_time, '%m-%Y') AS m, count(request_time) AS r
FROM web_log
WHERE
date(request_time) >= date_sub(curdate(), interval 12 month)
AND
date(request_time) <= date_add(curdate(), interval 6 month)
GROUP BY month(request_time)
ORDER BY request_time ASC;) T2
ON T1.m=T2.m
ORDER BY T1.m
Output will be:
m b r
10-2013 15 null
11-2013 6 null
12-2013 13 null
01-2014 10 null
02-2014 10 null
03-2014 25 45
04-2014 1 35