Selecting Columns in the Planning Table 
You can select sections of the planning table for further processing. For example, you might select a section of the planning table and change its period split in order to plan in greater detail; or you might decide to run the forecast for a limited section of the planning horizon.
To select a period split, double-click on that column or position the cursor on its heading, and choose Edit
To select a block, select the first and the last period split in the block.
To select all periods starting from a specific column, position the cursor on the period heading in that column and choose Edit ® Select ® Select from column.
To deselect all periods, choose Edit ® Select ® Deselect periods.
To deselect all periods starting from a specific column, position the cursor on the period heading in that column and choose Edit ® Select ® Deselect from column.