Unknown object type ‘…’ used in a CREATE, DROP, or ALTER statement (Msg 343)

Let’s consider the error “Unknown object type ‘…’ used in a CREATE, DROP, or ALTER statement” on the following example:

There is a need to add one more column “Column4” in the table “Table_1” which located in the database “Adventureworks”. To execute this operation was used next syntax

ALTER Table_1 
ADD Column4 INT;

But column was not added and from the SQL Server was received the following message:

Msg 343, Level 15, State 1, Line 3
Unknown object type 'Table_1' used in a CREATE, DROP, or ALTER statement.

This error occurs because SQL Server does not understand what to ALTER. In this case, it is necessary just to add TABLE after ALTER

ALTER TABLE Table_1 
ADD Column4 INT;