The UPDATE Statement, SQL Tutorial

This page discusses - The UPDATE Statement, SQL Tutorial

The UPDATE Statement, SQL Tutorial

The UPDATE Statement

     

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.

 

 

 

 

emp_name Position Salary email_id
Amar Designer 8000 [email protected]

If we want to change the salary to the employee with a emp_name of "Amar" then we should use the following SQL statement :

Syntax:

UPDATE 'table_name' SET 'field_name' = 'new_value'
WHERE 'field_name' = 'field_value';

for example: 
 
UPDATE Person SET Salary = 10000
WHERE emp_name = 'Amar';

The output of the above code will be :

emp_name Position Salary email_id
Amar Designer 10000 [email protected]


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 = '[email protected]', Position = 'Programmer'
WHERE emp_name = 'Amar';

The output of the above code will be:

emp_name Position Salary email_id
Amar Programmer 10000 [email protected]

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