我想将数组对象中的数组字段值连接成一个字符串字段。以下是现有文档格式:
{
"no" : "123456789",
"date" : ISODate("2020-04-01T05:19:02.263+0000"),
"notes" : [
{
"_id" : ObjectId("5b55aabe0550de0021097bf0"),
"term" : "BLA BLA"
},
{
"_id" : ObjectId("5b55aabe0550de0021097bf1"),
"term" : "BLA BLA BLA"
},
{
"_id" : ObjectId("5b55aabf0550de0021097ed2"),
"term" : "BLA"
}
],
"client" : "John Doe"
}
所需文件格式:
{
"no" : "123456789",
"date" : ISODate("2020-04-01T05:19:02.263+0000"),
"notes" : "BLA BLA \n BLA BLA BLA \n BLA",
"client" : "John Doe"
}
尝试使用 $project :
{ "$project": {
"notes": {
"$map": {
"input": "$notes",
"as": "u",
"in": {
"name": { "$concat" : [ "$$u.term", "\\n" ] }
}
}
}
}
}
但是这会返回这个:
{
"no" : "123456789",
"date" : ISODate("2020-04-01T05:19:02.263+0000"),
"client" : "John Doe"
"notes" : [
{
"name" : "BLA \n"
},
{
"name" : "BLA BLA \n"
},
{
"name" : "BLA BLA BLA \n"
}
]
}
如何将其转换为所需格式?非常感谢您的任何想法!
编辑:
如果我们尝试将数组字段值相加,而不进行分组,该怎么做呢?
现有格式:
{
"sale" : {
"bills" : [
{
"billNo" : "1234567890",
"billAmt" : NumberInt(1070),
"tax" : NumberInt(70)
}
]
},
"no" : "123456789",
"date" : ISODate("2020-04-01T05:19:02.263+0000")
}
Required :
{
"no" : "123456789",
"date" : ISODate("2020-04-01T05:19:02.263+0000"),
"total" : NumberInt(1140)
}