MongoDb去重和MySql去重

db.getCollection('order_trade_info').aggregate([     {         $group: { _id: {order_id: '$order_id'},count: {$sum: 1},dups: {$addToSet: '$_id'}}     },     {         $match: {count: {$gt: 1}}     } ]).forEach(function(doc){     doc.dups.shift();     db.getCollection('order_trade_info').remove({_id: {$in: doc.dups}}); })

Mysql
1.根据one列查询重复的数据(根据单列判断重复)
SELECT * FROM testdelete
WHERE ONE IN (SELECT ONE FROM testdelete GROUP BY ONE HAVING COUNT(ONE) > 1)

DELETE FRO

MongoDb去重和MySql去重最先出现在Python成神之路。