我在mongodb中有以下客户订单数据
"_id" : 7,
"customer name" : "John Smith",
"OrderItem" : [
{
"product_category" : "Mobile",
"price" : 900
},
{
"product_category" : "Computer",
"price" : 4200.48
},
{
"product_category" : "TV",
"price" : 670.20
},
{
"product_category" : "TV",
"price" : 960.52
}
]
我需要将每个产品类别平均化,如下所示:
"_id" : 7,
"customer name" : "John Smith",
"OrderItem" : [
{
"product_category" : "Mobile",
"price" : 900
},
{
"product_category" : "Computer",
"price" : 4200.48
},
{
"product_category" : "TV",
"price" : 815.36
}
]
我尝试使用$unwind,但不确定如何对它们进行分组。有帮助吗?