在MySQL表中插入重复记录时显示错误

为此，您可以使用UNIQUEKEY。让我们首先创建一个表-

create table DemoTable1553 -> ( -> EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> EmployeeName varchar(20), -> EmployeeSalary int -> );

这是添加唯一键的查询-

alter table DemoTable1553 add unique(EmployeeSalary); Records: 0 Duplicates: 0 Warnings: 0

使用插入命令在表中插入一些记录-

insert into DemoTable1553(EmployeeName,EmployeeSalary) values(Chris,45000); insert into DemoTable1553(EmployeeName,EmployeeSalary) values(David,35000); insert into DemoTable1553(EmployeeName,EmployeeSalary) values(Sam,25000); insert into DemoTable1553(EmployeeName,EmployeeSalary) values(Carol,45000); ERROR 1062 (23000): Duplicate entry 45000 for key EmployeeSalary

使用select语句显示表中的所有记录-

select * from DemoTable1553;

这将产生以下输出-

+------------+--------------+----------------+ | EmployeeId | EmployeeName | EmployeeSalary | +------------+--------------+----------------+ | 1 | Chris | 45000 | | 2 | David | 35000 | | 3 | Sam | 25000 | +------------+--------------+----------------+ 3 rows in set (0.00 sec)