Columns are almost never used as a battle formation, as they are primarily used to quickly march fighters from one place to another. However, a quick turn to the right or left can make a long column into a very effective shieldwall.
A column is a classical architectural feature used to support ceilings and domes but still allow a lot of movement and airflow at the ground level. It is very evident in the large medieval cathedrals. There are various different styles of columns, e.g. Ionic, Doric, Corinthian.