Mysql query to find number of occurrences of a value in a given date range

Question

I have a table with 7,000,000 rows and two columns: a name and a timestamp. The data in it look something like this:

NAME  - TIMESTAMP
Arnie - 2012-05-15 09:31:21
Arnie - 2012-05-15 10:31:21
Jethro - 2012-05-15 12:31:21
Regina - 2012-05-15 12:31:21
Beatriz - 2012-05-16 0:31:21
Jethro - 2012-05-15 08:31:21
Jethro - 2012-06-15 08:31:21
Jethro - 2012-06-16 08:31:21
Archie - 2012-06-16 09:31:21
Jethro - 2012-06-17 08:31:21

For every month since January 2012 I want to know how many times each name appeared that month so for the sample above I would want:

June 2012

Arnie - 2
Jethro - 2
Regina - 1
Beatriz - 1

July 2012

Jethro - 3
Archie - 1

What is the best way to do this? Also, Is there a way to run this as one query that groups the timestamps by month or should I just make a loop in PHP and run a separate query for each month?

I know this isn't super difficult and is surely covered in the docs but I'm confused as to the terms to search for.

Answer 1

you can use GROUP BY and get the count , you can use MONTHNAME

SELECT Name, MONTHNAME(TIMESTAMP) AS Month, COUNT(*) AS count
FROM Table1
GROUP BY NAME, MONTHNAME(TIMESTAMP)

Answer 2

Try this:

select date_format(timestamp, '%Y %M') as yyyymm, name, count(*)
from table t
group by date_format(timestamp, '%Y %M'), name
order by min(timestamp), name;

Note that the output format is slightly different from what you propose. This adds the year/month to each row as a separate column. This format is more consistent with relational result sets.