Count number of rows in each group in MySQLi

Question

I know this is basic but I find it tricky and couldn't quite phrase the question right in order to find the answer.

What I'd like to do is take these tables -

Table names
name   | nameID |
-----------------
Jhon   | 1
Bob    | 2
George | 3
Kim    | 4

Table mark
nameID | child
--------------
1      | 0
1      | 0
1      | 1
2      | 1
2      | 0
2      | 1
3      | 0
3      | 0
4      | 1
4      | 1
4      | 1
4      | 0

And then count how many times each name from table names appears in table mark with child=1, so you'll get:

name   | count
--------------
Jhon   | 1
Bob    | 2
Kim    | 3

Answer 1

try this.

select n.name, count(*)
from names n, mark m
where n.nameID = m.nameID and m.child = '1'
group by n.name