将重复在Postgresql中分组

Question

我要查询的是有多少库存入库，我如何将所有重复项归为一类，以便所有数量都为一个，而同一产品没有多次显示？我将发布一个屏幕截图，以显示我得到的信息和正在使用的代码。 谢谢

Duplicates example

select b.qty, a.part, a.desc1, a.main_supplier as supplier_acc_no, c.name as 
 supplier_name, a.main_mpn, a.date_receipt as date_booked_in
from public.stock as a
inner JOIN public.sthist AS b ON a.part = b.part
inner join public.supplier as c on a.main_supplier = c.account
where a.date_receipt > date_trunc('day', CURRENT_DATE) - INTERVAL '2 days'
and b.tran_type = 'POGRN'

Answer 1

sum和group by（以及任何非group-by表达式的适当功能）。例如，

select sum(b.qty), a.part, min(a.desc1), 
min(a.main_supplier) as supplier_acc_no, min(c.name) as supplier_name, 
min(a.main_mpn), min(a.date_receipt) as date_booked_in
from public.stock as a
inner JOIN public.sthist AS b ON a.part = b.part
inner join public.supplier as c on a.main_supplier = c.account
where a.date_receipt > date_trunc('day', CURRENT_DATE) - INTERVAL '2 days'
and b.tran_type = 'POGRN'
group by a.part