No entry in B1 unless A1 has a date AND it is earlier

[Mr X Z]

Hello all
Wonder if this is possible. I realise Data Validation caters for
restriction of dates but how do I stop any entry being made in B1
unless first there is an entry in A1?

Many thnks

ML

 

[Dave Peterson]

I did this in xl2003:

With B1 the active cell:
Data|Validation
Settings tab
Custom
Formula: =AND(ISNUMBER(A1),ISNUMBER(B1),A1<B1)
and made sure that "Ignore Blank" is not checked.

Be aware that this won't help if A1 is changed after the entry is made in B1.

I'd add a warning message in C1(?) that showed up if the entries were not
correct--big, red, letters.

(In fact, I wouldn't use data|validation. I'd just use that helper cell with
the warning message.)

 

[Mr X Z]

I did this in xl2003:

With B1 the active cell:
Data|Validation
Settings tab
Custom
Formula:  =AND(ISNUMBER(A1),ISNUMBER(B1),A1<B1)
and made sure that "Ignore Blank" is not checked.

Be aware that this won't help if A1 is changed after the entry is made inB1.

I'd add a warning message in C1(?) that showed up if the entries were not
correct--big, red, letters.

(In fact, I wouldn't use data|validation.  I'd just use that helper cell with
the warning message.)

Thanks Dave - I'll give it a try (I am using Xl2003).
If you have a spare mo please have a look at the discussion here -

http://groups.google.com/group/microsoft.public.excel.misc/browse_thread/thread/91199377d3f6505f#

ML