ALTER TABLE Statement :- Use the ALTER TABLE statement to :
– Add a new column
– Modify an existing column
– Define a default value for the new column
– Drop a column
Dropping a Table :- All data and structure in the table are deleted.
- Any pending transactions are committed.
- All indexes are dropped.
- All constraints are dropped.
- You cannot roll back the DROP TABLE statement.
- DROP TABLE dept30;
Creating a Table by Using a Subquery :- Create a table and insert rows by combining the CREATE TABLE statement and the AS subquery option.
- Match the numeric of specified columns to the numeric of subquery columns.
- Define columns with column names and default values.
- CREATE TABLE table [(column, column...)] AS subquery;
