mongodb 使用 where 条件聚合查询
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时间：2020-09-09 12:55:00 来源:igfitidea点击:
Aggregate query with where condition
提问by user1603400
How could the following SQL query be converted for Mongo:
如何为 Mongo 转换以下 SQL 查询：
SELECT KeyID, SUM(Qty)
FROM Table
WHERE Date <= '1998-12-01'
回答by Kay
Something like:
就像是：
db.myTable.aggregate([
{ $match: { mydate: { $lte: new Date('12/01/1998') } } },
{ $group: {
_id: "$keyid",
totalqty: { $sum: "$qty" }
}}
])
回答by Ravinath
Can use this -
可以用这个——
db.schoolexamregistration.aggregate([
{ $match: {"exam_session_id":"1523850138707"} },{
$lookup:
{
from: "student",
localField: "nic_ppt",
foreignField: "nic_ppt",
as: "student_detail"
}
}
])
