Mysql query using where and group by clause

Question

I have the following table.

mysql> select * from consumer9;
+------------+--------------+-------------------+
| Service_ID | Service_Type | consumer_feedb         


        

Answer 1

The following query should work.

select Service_ID, Service_Type, sum(consumer_feedback) 
from consumer9 
where Service_Type=Printer
group by Service_ID, Service_Type;

Remember, the where clause goes before the group by clause and all non-aggregated terms in the select part will have to be present in the group by clause.