Question

I have the following query:

SELECT num_hours, rate, st.tech_code
FROM ost_hours ht
LEFT JOIN ost_staff st ON ht.tech_code = st.tech_code
LIMIT 0 , 30

which results in the following:

num_hours   rate            tech_code
20          overtime_rate   2
4           overtime_rate   1
10          normal_rate     1
1           overtime_rate   4
1           overtime_rate   4
2           normal_rate     4
3           normal_rate     4
1.5         normal_rate     6
1.5         normal_rate     6
2           normal_rate     4
1           normal_rate     4

What I want it to result in is a sum per rate for each tech_code, so for example for tech codes 4 and 6 it would be the following:

total_hours rate            tech_code
8           normal_rate     4
2           overtime_rate   4
3           normal_rate     6

I hope that’s clear, everything I’ve done has resulted in unexpected and inaccurate data. I assume I need something to do with group by but every time I try something the result is totally bizarre.

Edit: Changed confusing “count” to “sum”

Answer 1

select sum(num_hours) as total_hours, 
    rate,
    st.tech_code
from ost_hours ht
left join ost_staff st on ht.tech_code = st.tech_code
group by rate,
    st.tech_code