user1212548 user1212548 - 3 months ago 28
MySQL Question

MYSQL array aggregate function like PostgreSQL array_agg

I got two tables on MYSQL, I wonder if there is any aggregate function on MYSQL as array_agg() FROM postgreSQL.

TABLE 1 properties Only have 8 records
TABLE 2 records who captured the property, so sometimes can be 1 or n times for the same property, and I got this Qry:

SELECT p.id, pcb.users_admin_id as uid
FROM properties p
INNER JOIN prop_captured_by pcb ON p.id = pcb.property_id
-- GROUP BY p.id

id uid
200 1
200 80
202 1
202 80
211 1
211 10
211 81
215 10 ...


If I use the GROUP BY part I get this:

id uid
200 1
202 1
211 1
215 10 ...


Losing any other data than the first value for users_admin_id. I know that I can achieve my desired result with array_agg() function from postgreSQL but I can't figured out how to do it on MYSQL.

This is my desire Result:

id uid
200 1,80 //an array, I don't mind about the separator, could be anything.
202 1,80
211 1,10,81
215 10 ...


I have tried UNION, GROUP BY, INNER JOIN... no luck...
Any pointers?

UPDATE

I am using the many to many relations from this guy. Hopes it is useful for someone else. I needed to add the user's name from a third table, so the final query looks like this:

SELECT p.id, group_concat(pcb.users_admin_id) as uid, group_concat(ua.name) as uin
FROM properties p
INNER JOIN prop_captured_by pcb ON p.id = pcb.property_id
INNER JOIN users_admin ua ON ua.id = pcb.users_admin_id
group by p.id;

Answer

You want to use GROUP_CONCAT() like

SELECT p.id, group_concat(pcb.users_admin_id) as uid
FROM properties p
INNER JOIN prop_captured_by pcb 
ON p.id = pcb.property_id
group by p.id;