The SQL UPDATE statement is used to update data stored in database tables.
SQL UPDATE Statement Syntax
UPDATE TableName SET Column1=Value1, Column2=Value2, ... WHERE conditions
The WHERE clause is very important for SQL UPDATE statement. If it’s omitted, all records will be modified.
SQL UPDATE Example
Table: 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 |
We need to change Dona Earl’s department to Finance:
UPDATE Employees SET Department='Finance' WHERE FirstName='Dona' AND LastName='Earl'
The Employees table will be updated to:
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 |
Example 2
We want to raise Tony Oakes’s salary by $5000:
UPDATE Employees SET Salary = Salary + 5000 WHERE FirstName='Tony' AND LastName='Oakes'
Now, the table will look like:
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 |