Thanks guys for the help so far.

I've discovered that what I thought was a potential link actually isn't so after all your advice it's not going to help me in this scenario.

That being said I think I have found another potential to link my two data sets together.

Example I table 1 we have "708698"

In table 2 we have "Internet Card Payment Auth Code: 708698"

Is there anyway in SQL that you could say join 708698 to Internet Card Payment Auth Code: 708698 by looking in the table 2 field to match the 708698?