modify the existing records in a table

UPDATE table_name
SET column1 = value1, colume2 = value2, ...
WHERE condition

Note: Be careful when updating records in a table! Use WHERE to specify the column you want to update, or all columns in the table will be update.

update one record

UPDATE Customers
SET ContactName = 'Alfred Schmidt', City= 'Frankfurt'
WHERE CustomerID = 1;

update multiple records

UPDATE Customers
SET ContactName='Juan'
WHERE Country='Mexico';

Warning!!!

Do not omit WHERE if you don’t want to update all the records