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What is the command to modify the table structure in sql statement?

The command in the SQL statement to modify the table structure is ALTER TABLE.

ALTER TABLE statement

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

SQL ALTER TABLE syntax

To add columns to the table, please use the following syntax:

ALTER TABLE table_name
ADD column_name datatype

To delete columns in the table, please use the following syntax (Please note that some database systems do not allow this way of deleting columns in database tables):

ALTER TABLE table_name
DROP COLUMN column_name

To change the data type of a column in a table, use the following syntax:

SQL Server / MS Access:

ALTER TABLE table_name
ALTER COLUMN column_name datatype

My SQL / Oracle:

ALTER TABLE table_name
MODIFY COLUMN column_name datatype

Oracle 10G and later versions:

ALTER TABLE table_name
MODIFY column_name datatype;

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