如何在sql中使用sum来比较今天和上周的销售额？

Question

如何比较postresql和上周在同一个查询中的产品值的总和？举个例子，第一列显示J天所有奶昔的和，然后是j-7，第三列是显示演化？

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Answer 1

我这样做是用连接SQL查询的

Select a.restaurant, a.nb_milkshake_J, b.nb_milkshake_J_7, 
 (((a.nb_milkshake_J - b.nb_milkshake_J_7)/b.nb_milkshake_J_7)*100)
from 
(select restaurant,cast(sum(quantite) as float) as nb_milkshake_J   
from public.ventes_restaurant
where produit_groupe like 'MILKSHAKES'
and produit like 'MILKSHAKES%'
and date_commande ='2021/11/26' 
group by restaurant,date_commande 
) a full join 
(select restaurant,cast(sum(quantite) as float) as nb_milkshake_J_7   
from public.ventes_restaurant
where produit_groupe like 'MILKSHAKES'
and produit like 'MILKSHAKES%'
and date_commande ='2021/11/19' 
group by restaurant,date_commande) b  on a.restaurant = b.restaurant