UPDATE server_list_server SET world_id=regexp_replace(ip,'wg(\\d+)\.glwsy\.szgla\.com;?','\\1') WHERE ip REGEXP 'wg(\\d+)\.glwsy\.szgla\.com;?' AND world_id!=regexp_replace(ip,'wg(\\d+)\.glwsy\.szgla\.com;?','\\1'); REGEXP regexp_replace \\1 is the placeholder for matched group
Category: database
Change value for a PK column with AUTO_INCREMENT in mysql
show create table TABLE_NAME; // Check current AUTO_INCREMENT value update IGNORE TABLE_NAME set primary_field = 'value' ...; // Change the column value with IGNORE keyword alter table TABLE_NAME AUTO_INCREMENT = 50; // Set AUTO_INCREMENT show create table TABLE_NAME; // Check current AUTO_INCREMENT value again
Aggregate in Mongodb in C#
Filter record from collection “OperationSession”, sort by “WorldId” descending, then group by “WorldId”, then pick first record from each group, then sort result: Way #1: db.getCollection('OperationSession').aggregate( [ { "$match": {"ActivityId":74,"GameId":2109} }, { "$sort":{ "CreateTime" : -1} }, { "$group": { _id:"$WorldId", SessionId:{"$first": "$_id" }, GameId:{"$first": "$GameId" }, WorldId:{"$first": "$WorldId" }, ActivityId:{"$first": "$ActivityId" }, Type:{"$first": "$Type" …
[MongoDB] Read preference in a transaction must be primary
MongoDB 4.0.3 ReplicaSet MongoDB.Driver for .net Core 2.7.3 在Connection String中配置了readPreference=secondaryPreferred: mongodb://user:password@mongod-1:27017,mongod-2:27017,mongod-3:27017/DBName?connect=replicaSet&readPreference=secondaryPreferred 然后在一个Transaction中读取数据报错：”Read preference in a transaction must be primary”, Transaction中的读取不能使用secondaryPreferred
MongoDB中使用$rename指令修改字段名
如下所示：把collection Policy中的Type为1的所有document的UserID字段修改为UserName, multi为true表明修改所有记录，upsert为false表明记录不存在则不创建： db.getCollection('Policy').update({"Type":1},{$rename:{'UserID': 'UserName'}},{"multi" : true, "upsert" : false}) 参考：https://docs.mongodb.com/manual/reference/operator/update/rename/