sqlite - Using sql to sum with multiple table calls -

i'll down point. have 3 tables structured follows:

orders:

i_id |  o_id  |  quantity -----+--------+----------   1  |   1    |     5   2  |   2    |     2   1  |   3    |     3   1  |   4    |     3   2  |   5    |     4 

orderinfos:

o_id  |  c_id ------+------------  1    |   1  2    |   2  3    |   2  4    |   1  5    |   2 

customers:

    c_id  |  name_id ----------+----------      1    |   100001      2    |   100002 

then resulting chart be:

    name_id |   i_id   |  quantity  -----------+----------+----------  100001     |    1     |    8  100002     |    2     |    6  100002     |    1     |    3 

so basically, have summary of (in case, orders) quantity, , each order has customer id , item name associated. resulting chart gives quantity per customer, per item, in descending order customer. first implementation this:

select quantcust.custidname, quantcust.itemid, quantcust.quant     (select o.i_id itemid,     c.name_id custidname,     sum(o.quantity) quant     orders o, orderinfos i, customers c     o.o_id = i.o_id , i.c_id = c.c_id     group o.i_id, i.c_id) quantcust order quantcust.custid, quantcust.quant desc; 

which not print correct values.

i think you're close approach, recommend using explicit join syntax, , using aggregate sum (along group by) totals:

select c.name_id, i_id, sum(quant) quant customers c inner join orderinfo oi on c.c_id = oi.c_id inner join orders o on oi.o_id = o.o_id group c.name_id, i_id order c.name_id, quant desc 

this works me sample data, giving desired output indicate.