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Difference Between TRUNCATE, DELETE and DROP commands

1.DELETE
  • The DELETE command is used to remove rows from a table. 
  • A WHERE clause can be used to  remove some rows. 
  • If no WHERE condition is specified, all rows will be removed. 
  • After performing a DELETE operation you need to COMMIT or ROLLBACK the transaction to make the change permanent or to undo it.
  • Note that this operation will cause all DELETE triggers on the table to fire.
2.TRUNCATE
  • TRUNCATE removes all rows from a table. 
  • No triggers will be fired. 
  • Not able to perform ROLLBACK operation.
  • TRUNCATE is faster then DELETE and doesn't use as much undo space as a DELETE.
3.DROP
  • The DROP command removes a table from the database.
  •  All the tables' rows, indexes and privileges will also be removed. 
  • No DML triggers will be fired. 
  • Not able to perform ROLLBACK operation.
SOME MORE DIFFERENCES

DROP and TRUNCATE are DDL commands, whereas DELETE is a DML command. 
DELETE operations can be ROLLBACK (undone), while DROP and TRUNCATE operations cannot be ROLLBACK.
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