Required Entry

[Jeff]

I am creating a spreadsheet and I need to ensure data
entry is required in a column when data has been enterd
into a previous column. Any help on this would be much
appreciated. Thanks.

 

[Dave Peterson]

I would use an additional column.

Say B3 has to have something in it when A3 has data in it.

In C3:

=IF(A3="","",IF(B3<>"","","Please enter something in B3"))
Format it in nice big bold red letters.