Merge Two Sheets, Like SQL: Full Outer Join

I have two Worksheets: ' Forecast' and 'Actuals'

'Key' for Rows in both sheets is:
ProjectNumber, Change Order Number, Role (Text Desc)

Data for Forecast is Jan, Feb, Mar-> Project Forecast in Days

Data for Actuals is Jan, Feb, Mar-> Project Actuals in Days

Rows in Forecast Sheet may not have matching Actuals (e.g. Project not yet started), AND VICE VERSA (e.g. a new Role may have been needed on a Project, not anticipated at Forecast time, or Actuals are being recorded for a Project without a Forecast being created).

What I would like to do is:
Create a single Sheet with the same key as above,
Each row containing columns for 12 months of Forecast Data, and a further 12 of Actuals Data.
Where an exact key match is found, Row will have both sets of Data (one set from each sheet). Where a match is not found, then Row will have either Forecast Data OR Actuals Data only.

This task needs to be repeated, so needs to be either a straightforward manual procedure, or a Macro.

I have tried various combinations of VLOOKUP, but that doesn't help pull in data that has no matching key. I realise I could manually create a 'keys' Sheet, de-dup and use VLOOKUP into both sheets, but this seems horribly long-winded.