A already assigned variable cannot be assigned twice You can make the variable change over to a new one or call a whole new one to assign one without a value or It might be possible to do v=n (v is variable and n is number / value)
The SQL is used to change a table's structure by:
The use of the SQL ALTER TABLE command.
<h3>How is it done?</h3>
The SQL ALTER TABLE command is known to be that which is often used to alter the structure of an existing table.
It is known to help one to be able to add or delete columns, make or destroy indexes, alter the kinds of existing columns, rename columns or the table itself.
Note that It can also be used to alter the comment for any kind of table and type of the table therein.
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