How can I add a column to a right join select query - mysql

Question

I am trying to find a way to add a country code to a database call record based on a phone number column. I have a table with countries and their dialling codes called countries. I can query all records and add the country code after but I need to be able to filter and paginate the results.
I am working with a system I don't have much control over so adding new columns to tables or rewriting large blocks of code isn't really an option. This is what I have to work with.
Countries Table.
id
name
dialling_code
1
Ireland
353
2
America
1
Call Record table.
id
startdatetime
enddatetime
route_id
phonenumber
duration_seconds
1
2014-12-18 18:51:12
2014-12-18 18:52:12
23
3538700000
60
2
2014-12-18 17:41:02
2014-12-18 17:43:02
43
18700000
120
Routes table.
id
number
enabled
23
1234567890
1
43
0987654321
1
I need to get sum values of duration, total unique phone numbers all grouped by route_id, route_number but now we need to group these results by country_id so we can group callers by country. I use the mysql query below to get sum values of duration, total unique phone numbers all grouped by route_id, route_number. This query was written by another developer a long time ago.
SELECT
phone_number,
route_number,
COUNT(callrecord_id) AS total_calls,
SUM(duration_sec) AS total_duration,
callrecord_join.route_id
FROM routes
RIGHT JOIN (
SELECT
DATE(a.startdatetime) AS call_date,
a.id AS callrecord_id,
a.route_id AS route_id,
a.phonenumber AS phone_number,
a.duration_seconds as duration_sec,
b.inboundnumber AS route_number,
FROM callrecord AS a
INNER JOIN routes AS b ON a.route_id = b.id
WHERE DATE_FORMAT(a.startdatetime, '%Y-%m-%d') >= '2014-12-18'
AND DATE_FORMAT(a.startdatetime, '%Y-%m-%d') <= '2014-12-18'
AND b.isenabled = 1
) AS callrecord_join ON routes.id = callrecord_join.route_id
GROUP BY route_id, route_number
LIMIT 10 offset 0;
I have everything up to adding a country_id in the right join table so I can group by the country_id.
I know I could loop through each country using php and get the results using a where clause, something like the below but I cannot paginate these results or filter them easily.
WHERE LEFT(a.phonenumber, strlen($dialling_code)) = $dialling_code
How can I use the countries table to add a column to the join table query with the country id so I can group by route_id, route_number and country_id? Something like the table below.
id
startdatetime
enddatetime
route_id
phonenumber
duration_seconds
country_id
1
2014-12-18 18:51:12
2014-12-18 18:52:12
23
3538700000
60
1
2
2014-12-18 17:41:02
2014-12-18 17:43:02
43
18700000
120
2

Answer 1

The RIGHT JOIN from routes to callrecord_join serves no purpose, as you already have the INNER JOIN between routes and callrecord in the sub-query, which is on the righthand side of the join.
You can use the join you have described -
JOIN countries c ON LEFT(a.phonenumber, LENGTH(c.dialling_code)) = c.dialling_code
but it will give the same result as:
JOIN countries c ON a.phonenumber LIKE CONCAT(c.dialling_code, '%')
which should be slightly less expensive.
You should test the join to countries to make sure none of your numbers in callrecord join to multiple countries. Some international dialling codes are ambiguous, so it depends on which list of dialling codes you are using.
SELECT a.*, COUNT(*), GROUP_CONCAT(c.dialling_code)
FROM callrecord a
JOIN country c ON a.phonenumber LIKE CONCAT(c.dialling_code, '%')
GROUP BY a.id
HAVING COUNT(*) > 1;
Obviously, you will need to batch the above query if your dataset is very large.
I hope I am not grossly over-simplifying things, but from what I understand of your question the query is just:
SELECT
r.id AS route_id,
r.number AS route_number,
c.name AS country_name,
SUM(a.duration_seconds) AS total_duration,
COUNT(a.id) AS total_calls,
COUNT(DISTINCT a.phonenumber) AS unique_numbers
FROM callrecord AS a
JOIN routes AS r ON a.route_id = r.id
JOIN countries c ON a.phonenumber LIKE CONCAT(c.dialling_code, '%')
WHERE a.startdatetime >= '2014-12-18'
AND a.startdatetime < '2014-12-19'
AND r.isenabled = 1
GROUP BY r.id, r.number, c.name
LIMIT 10 offset 0;
Please note the removal of DATE_FORMAT() from the startdatetime to make these criteria sargable, assuming a suitable index is available.