sql - Trying to Group Rows -

i thought distinct statement group orders.customer_num, doesn't seem case. believe has expression in select statement. new sql.

select distinct orders.customer_num "customer number",         count(orders.order_num) "number of orders",        sum(items.quantity) "total quantity", stock.unit_price "unit price",        items.quantity * stock.unit_price "total price" orders,      items,      stock orders.order_num = items.order_num   , items.stock_num = stock.stock_num group orders.customer_num, items.quantity, stock.unit_price order orders.customer_num;  

attached pic showing getting. my result

your stock.unit_price seems unique. logically selects unit_price per item. either need discard stock table , related join conditions or sum up