建表及插入数据语句:mysql> create table salary(userid int,salary decimal(9,2));Query OK, 0 rows affected (0.11 sec)mysql> insert into salary values(1,1000),(2,2000),(3,3000),(4,4000),(5,5000),(1,null);Query OK, 6 rows affected (0.13 sec)Records: 6 Duplicates:…