•   SQL provides the UPDATE statement for changing data in a table. By using a single UPDATE statement, you can change one, some, or all rows in a table. The UPDATE statement uses the following syntax:

               UPDATE table_name

                      SET column_1 = expression_1, column_2 = expression_2,

                      . . . , column_n = expression_n

                     [WHERE predicates] ;

EXAMPLE:

               UPDATE table_name

              SET column1 = value1, column2 = value2, . . .

              WHERE condition;

THE UPDATE STATEMENT

•    The WHERE clause is optional. This clause specifies the rows that you’re updating. If you don’t use a WHERE clause, all the rows in the table are updated. The SET clause specifies the new values for the columns that you’re changing.

          UPDATE person

          SET street = '1225 Tremont St.',

             city = 'Boston',

             state = 'MA',

             country = 'USA',

             postal_code = '02138'

          WHERE person_id = 1;