如何使用$ split运算符进行聚合
我想在date字段上使用$ split运算符。
[{ "status": true, "beaconData" :{ "date" : "15/07/2017, 11:00", "charge" : 15, }, { "status": true, "beaconData" :{ "date" : "2/07/2017, 15:00", "charge" : 35, }, { "status": true, "beaconData" :{ "date" : "2/07/2017, 11:05", "charge" : 5, }]
我曾经这样用过
db.orders.aggregate([{$ project:{data:{$ split:[“$ beaconData.date”,“,”]},'status':1}}])
但错误返回像
“errmsg”:“exception:无效的操作符'$ split'”,
“代码”:15999,
//$split works in 3.4 u can use $substr in ur case if ur date is always in the same format you asked db.orders.aggregate( [ { $project: { data: { $substr: [ "$beaconData.date", 0, 9 ] } } } ] )