The UPDATE statement is used to modify the data in the database table through a specified criteria. In the given syntax of update statement the keyword SET is used to assign a new value to a selected columns. The statement also uses WHERE clause.
It simply work as a select statement, if the given criteria match with the table content then the selected row will be effected if not then the whole table will be effected.
Lets consider a record with a emp_name of "Amar" as shown below.
If we want to change the salary to the employee with a emp_name of "Amar" then we should use the following SQL statement :
UPDATE 'table_name' SET 'field_name' = 'new_value' WHERE 'field_name' = 'field_value';
UPDATE Person SET Salary = 10000 WHERE emp_name = 'Amar';
The output of the above code will be :
To Update several Columns in a Row: If we want to change the multiple values of a table like in employee table we want to change Position and email_id then we have to write the following code in which we set the email_id and position by SET keyword and putting condition by keyword WHERE for emp_name is 'Amar'.
UPDATE employee SET email_id = 'firstname.lastname@example.org', Position = 'Programmer' WHERE emp_name = 'Amar';
The output of the above code will be:
Posted on: April 18, 2011 If you enjoyed this post then why not add us on Google+? Add us to your Circles