I receive a new generation file each day about 40m records and 150 columns -
give or take both ways depending on the day. Columns can and do come and go
but- for the most part I am insensitive to this movement other than
location/order changing.

Each day I save the new generation file as a worksheet in a book where I
maintain historical data. Each day's worksheet receives the corresponding
name of the file generation; 100.01, 100.02, 100.03, 101.01, 102.03 you get
the idea.

My wish is to integrate a data sheet I have which feeds a large model with
the historical worksheets where I would have the ability to qry the same
handful of columns form within any historical worksheets by putting the name
of the worksheet/file generation desired in a single cell (i.e. 103.02 for
example).

My difficulty is that due to the large number of records it is impractical
for me to to use some of the solutions I found here as they would not allow
cell and column references to be copied down and across. Also, variability in
the columns is presenting a challence but on the bright side field/colunb
names do not change

I tend to believe I might be able to achieve this with indirect or offset
functions but I have little experience with these - otherwise i'm rather
proficient.

Thanks in advance.