To update record or data DELETE query is used.

Syntax:

DELETE FROM table_name WHERE condition;

First show all data from contact table:

SELECT * FROM contact;

DELETE data where id = 14:

DELETE FROM contact WHERE id = 14;

After deleting again show all data from contact table:

SELECT * FROM contact;

DELETE all data from table:

Syntax:

DELETE FROM table_name;

Be care fully about delete query. You can't restore data.