Modifying Data

During everyday operations in a company, data constantly requires changes. You can make changes to existing records in a table by performing an UPDATE operation. While performing an UPDATE, you need to specify the column(s) and row that you are modifying as well as the new value(s).

UPDATE Statement

Syntax

UPDATE [table] SET  column1 = value1, column2 = value2 ...)

 		WHERE colunm1 = value1 AND column2 = value2

Example: Simple UPDATE

UPDATE EMPLOYEES SET SALARY = SALARY * 1.05 

      	WHERE EMPLOYEE_ID = 7499

      

Example: Using Sub-query

UPDATE EMPLOYEES SET SALARY = SALARY * 1.05 

      	WHERE DEPARTMENT_ID = (SELECT DEPARTMENT_ID FROM DEPARTMENTS WHERE DEPARTMENT_NAME = ’SALES’)