Sunday, 15 May 2011

SQL UPDATE Statement

SQL UPDATE Statement

The UPDATE Statement is used to modify the existing rows in a table.

The Syntax for SQL UPDATE Command is:

UPDATE table_name
SET column_name1 = value1,
column_name2 = value2, ...
[WHERE condition]

• table_name - the table name which has to be updated.
• column_name1, column_name2.. - the columns that gets changed.
• value1, value2... - are the new values.

NOTE:In the Update statement, WHERE clause identifies the rows that get affected. If you do not include the WHERE clause, column values for all the rows get affected.

For Example: To update the location of an employee, the sql update query would be like,

UPDATE employee
SET location ='Mysore'
WHERE id = 101;

To change the salaries of all the employees, the query would be,

UPDATE employee
SET salary = salary + (salary * 0.2);

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