DELETE

UPDATE 2

Structured Query Language DELETE 1

DELETE 2

Hint: Be careful and deactivate AUTOCOMMIT.

The DELETE command removes rows from a table.

DELETE FROM <tablename>
WHERE       <search_condition>;

The syntax is straightforward as we do not need to specify any column name - rows are deleted as a whole and not partly. As usual, the search condition specifies the criterion which identifies the affected rows. It can involve zero, one, or more rows. If we omit the WHERE keyword and the search condition all rows are affected.

-- Delete one row
DELETE FROM person
WHERE  lastname = 'Burton';

-- It's only a test. Restore the row.
ROLLBACK;

The information about Mr. Burton was deleted and restored again.

We present some more information about the DELETE command here. There are also some comments to the interconnection with the TRUNCATE command.

-- Delete one row
DELETE FROM hobby
WHERE  hobbyname = 'Yoga';
-- or: WHERE  id = 6;

ROLLBACK; -- if we want to restore the row
COMMIT;   -- if we want to commit our work

-- Check the result
SELECT * FROM hobby;

-- compact syntax - great impact
DELETE FROM person_hobby;

-- Check the result
SELECT * FROM person_hobby;

-- restore everything
ROLLBACK;

UPDATE 2

Structured Query Language DELETE 1

DELETE 2