There is a way to get a list of all the table columns in the Query Editor window by dragging column names from Object Explorer in SQL Server Management Studio.
In Object Explorer: Click 'Columns', hold and drag it on to the Query Editor window:
Comma separated list of all the table columns will show up:
You can drag column names one by one from Object Explorer by holding and dragging them on to the Query Editor window:
You can also drag other object names like table names, view names, function names, stored procedure names, database names etc. from Object Explorer window: