Mongodb 删除重复数据

db.getCollection("T_ZXJC_FSSSData").aggregate([
    {//聚合字段
        $group:{_id:{dwmc:'$dwmc',pfkmc:"$pfkmc",pwxkzbh:"$pwxkzbh",mn:"$mn",xkpfkwybm:"$xkpfkwybm",data_time:"$data_time",sjc:"$sjc"},count:{$sum:1},dups:{$addToSet:'$_id'}}
    },
    {
        $match:{count:{$gt:1}}  //大于1的记录
    } 
    ])	
		.forEach(function(it){
         it.dups.shift(); //去掉一个
         db.getCollection("T_ZXJC_FSSSData").remove({_id: {$in: it.dups}}); 
    });