How to extract values from base sheet to new sheets, without blanks and including expanding ranges

[Captain Hindsight]

I have a tab in Excel in a normal database style.

One of the columns categorises the items.

I then have subsequent tabs - one per category where I want formulas to extract all the entries in that category from the base sheet.

I can do this with a vlookup or IF function, but the two criteria that make it more difficult are:

1. I will constantly be adding rows to the base data so the range will change
2. I do not want any blanks to be on my sub-tabs. e.g. vlookup returns value in B2, #N/A in B3 and B4, value in B5, etc. I want it to show the value in B2 as it would, then in B3 show the value that would have been in B5

Thanks