Data validation based on value from another column

It depends on what "the rest of the row" means. The data validation would not be in column A or B, it would be in the "rest of the row". There would be a rule that says

=OR($A1="Planned",AND($A1="Unplanned",$B1<>""))

This would require that before the rest of the row can be filled in, either A must be Planned, or if it's Unplanned then B must have a value.

That is how you would do it with data validation. However, you may have other data validation requirements for those cells that get in the way.

Depending on the complexity of all of the validation you want to do, VBA would also be an option. It's not possible to say much more based on what you have described so far.

I don't understand what point you are making in your last post. The rest of the row has everything to do with this validation. The way to do the validation you described is not to put the data validation in G or H, but to put it in the rest of the row to prevent entries there if you have not made the required entries in G and H first. However, that will be problematic if there is other validation that needs to be done in the rest of the row.

So what do you mean by "required"? At what point in the process of completing the information do you want to make sure something has been entered in H if they select "Unplanned"?

I will try one more time. You are providing contradictory requirements.

anytime that the selected value in G is "Unplanned" then it should require them to provide H.

Ok, so if it's required, then they aren't allowed to enter any other data until they provide it.

If i were the one that was filling in for my team, i could enter a row with some information just so its captured and not forgotten.. and then come back at a later time to provide more or complete the whole row..

Oh, so it's not really required, because you are allowed to skip it and enter other data.

Ignoring the contradiction, here are the two ways that are best practices for the type of validation you seem to be describing.

Scenario 1: The typical way this is done in a user interface is if you enter Unplanned, then you should not be allowed to make any other entries until you make the entry for H. There are two ways to do this:

1. Use data validation in all of the cells in the row so that they will all reject input until the user has provided a value in H. That is the data validation rule I provided in post #2.
2. Use VBA to prevent the user from selecting any other cell until they have provided a value in H

Scenario 2: The alternative is when you have a form of data that must be submitted, and when you hit the Submit button, you check to see if the required data has been provided. If not you reject the Submit and put the user in the field where the data is missing. But that is not the situation you are describing; the user is entering data in worksheet rows, not a form. There appears to be no "submit" for a row, so you have to use the first scenario I described above.

Ill try and put together a sample file based on what is already known within our team and go from there, i agree, its not technically required before moving on, and maybe "validation" was not the correct title to use.
at the end of the day all we care about is that if you chose "unplanned" you provide notes/comments explaining why.. thats all..

may end up doing the vba method,