You could use a normalizing union query:
SELECT ID, FieldA as TheNumber
FROM [a table whose records have four fields]
UNION ALL
SELECT ID, FieldB
FROM [a table whose records have four fields]
UNION ALL
SELECT ID, FieldC
FROM [a table whose records have four fields]
UNION ALL
SELECT ID, FieldD
FROM [a table whose records have four fields];

Signature
Duane Hookom
MS Access MVP
> As suggested: Combined:=field1 & field2 & field3
> Resulted in
[quoted text clipped - 8 lines]
>
> When 1 is the ID and 2,3,4 are the unique numbers.