SQL UPDATE 语句用来更新数据表中的记录。
SQL UPDATE 语句语法
UPDATE TableName SET Column1=Value1, Column2=Value2, ... WHERE conditions
WHERE子句对SQL UPDATE非常重要,如果忽略,所有记录都将会被修改。
SQL UPDATE 范例
数据表: Employees
| EmployeeId | FirstName | LastName | Department | Salary |
|---|---|---|---|---|
| 203 | Mary | Fox | Finance | 78000 |
| 204 | Joe | Lanyon | Finance | 45800 |
| 303 | Dona | Earl | Development | 55000 |
| 304 | Tony | Oakes | Development | 49000 |
我们想将 Dona Earl 的部门改为Finance:
UPDATE Employees SET Department='Finance' WHERE FirstName='Dona' AND LastName='Earl'
Employees 表将会更新为:
| EmployeeId | FirstName | LastName | Department | Salary |
|---|---|---|---|---|
| 203 | Mary | Fox | Finance | 78000 |
| 204 | Joe | Lanyon | Finance | 45800 |
| 303 | Dona | Earl | Finance | 55000 |
| 304 | Tony | Oakes | Development | 49000 |
例2
我们想将Tony Oakes的工资加$5000:
UPDATE Employees SET Salary = Salary + 5000 WHERE FirstName='Tony' AND LastName='Oakes'
现在Employees表会如下所示:
| EmployeeId | FirstName | LastName | Department | Salary |
|---|---|---|---|---|
| 203 | Mary | Fox | Finance | 78000 |
| 204 | Joe | Lanyon | Finance | 45800 |
| 303 | Dona | Earl | Finance | 55000 |
| 304 | Tony | Oakes | Development | 54000 |
