The differences of several deletions in SQL

Drop

drop Can be used to delete a database （drop database Database name ）、 Delete data table （ use Database name  drop table Data sheet 1 name , Data sheet 2 name ） Or delete data table fields （use Database name alter table Data table name drop column Field name （ Column name ））.

It is worth noting that ：drop Statement will delete the structure of the table 、 Bound by dependence (constrain), trigger (trigger), Indexes (index); Stored procedures that depend on the table / The function will keep , But it became invalid state .

 

Truncate

Truncate Used to delete data in the data table , Only the data in the data table , Don't delete the table （ truncate table Data table name ）.

 

Delete

Delete ： Delete rows from a data table , You can delete a line , You can also delete all rows without deleting the data table （ Delete a line ：Delete from Data table name where Column name = value ）.