SQL Advanced Application (DROP, ALTER)

SQL revocation indexes, tables, and databases

By using the drop statement, you can easily delete indexes, tables, and databases

SQL DROP INDEX

To delete an index in a table by using the DROP INDEX command

Syntax for Microsoft Sqljet (and Microsoft Access)

DROP INDEX index_name on table_name

Syntax for MS SQL Server

DROP INDEX Table_name.index_name

Syntax for IBM DB2 and Oracle

DROP INDEX index_name

Syntax for MySQL

ALTER TABLE table_name DROP INDEX index_name

　　

SQL DROP TABLE

DROP TABLE statements are used to delete tables ( the structure, properties, and indexes of the table are also deleted )

DROP Table Name

　　

SQL DROP DATABASE

The DROP DATABASE statement is used to delete databases

DROP database name

　　

SQL TRUNCATE TABLE

If you want to delete only the data in the table and do not delete the table itself, use TRUNCATE table

TRUNCATE Table Name

　　

SQL ALTER TABLE

The ALTER table statement is used to add, modify, or delete columns in an existing table

SQL Advanced Application (DROP, ALTER)