原 sql 语句
SELECT `*`,GROUP_CONCAT(`invoice_number`) as `invoice_number_all`,ROUND(SUM(`invoice_amount`)/100,2) as `invoice_amount_all`,ROUND(SUM(`premium_amount`)/100,2) as `premium_amount_all` FROM `t_invoice` WHERE `id` != 0 GROUP BY `insurer_id`,`region_id`,`invoice_company_id`,`data_type`,`invoice_date`,`invoice_remark` ORDER BY `invoice_date` DESC LIMIT 0,15 刚开始用 mongo 数据库很多操作不会写。简单的还会,这是 mysql 查询分组后的结果,转换到 mongo 没有写正确导致查询不出数据。想问问这样的 sql 语句转 mongo 合适吗?还是要怎么处理呢!
db.t_invoice.aggregate({ $group: { _id: "$insurer_id"} }) 我这样写只能一个,多个我怎么写都报错,查询不出结果。而且字段名也不是我想要的 我把 _id 改成字段就开始报错! 
