Does ALTER TABLE drop table?

How can I alter a table without dropping it?

So to do that go to SQL Server and within Tools select Options. Now in the option window expand Designers and under that "Table and Database Designers" and uncheck the check box "Prevent saving changes that require table re-creation" then click OK.

Does ALTER TABLE delete existing data?

No it will not erase your data. It will add a column and all the existing data will be assigned null values in this column.

What happens to data when you alter the table structure?

It is important to consider how schema changes will affect the data in a table. Adding an extra column to a table will add an extra column to all existing rows, just as it would in a spreadsheet. Deleting a column means all data in that column will be lost forever.

Can we use drop with Alter?

The ALTER TABLE statement is used to add, delete, or modify columns in an existing table. The ALTER TABLE statement is also used to add and drop various constraints on an existing table.