sql server中的悲观锁和乐观锁

https://www.cnblogs.com/chenwolong/p/Lock.html

https://www.cnblogs.com/dengshaojun/p/3955826.html

https://docs.microsoft.com/en-us/sql/relational-databases/system-stored-procedures/sp-getapplock-transact-sql

https://www.sqlshack.com/locking-sql-server/