Mysql Selecting column from one table and count from another

Table1# t1 
id | name | include 
------------------- 
1 |   foo   | true 
2 |   bar   | true 
3 |   bum  | false

Table2# t2

id | some | table_1_id 
------------------------- 
1 |  42      | 1 
2 | 43       | 1 
3 | 42       | 2 
4 | 44       | 1 
5 | 44       | 3


Desired output:
name | count(some) 
------------------
 foo | 3 
 bar | 1

SOLUTION:
SELECT a.name, COUNT(r.some) FROM t1 a JOIN t2 r on a.id=r.table_1_id WHERE a.include = 'true' GROUP BY a.name


Columns you want to use in an aggregate function like sum() or count() must be left out of the group by clause. Only put the columns in there you want to be unique outputted.