Lookup Transformation Join Column Types

Does anyone have a clue as to why DT_R4, DT_R8 are not allowed as join columns? This means I cannot join tables on AccountNumbers, InvoiceNumbers, etc. What a pain...

We didn't include support for floating point joins, because of the inherent inability of computers to accurately compare two floating point numbers.

To make the comparisons consistent, we would need to introduce some sort of rounding and user specified precision. If we did not, you may might be now posting a question about why 1.75 is not equal to 1.75 J

I hardly every see people store invoice or account numbers as floating point, I would be interested to know why you made this choice.

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>>inability of computers to accurately compare two floating point numbers

I had forgotten about that little fact.

I do not store account numbers and other similar keys as a floating point data type. However, the access database that I am importing with SSIS was created (by my predecessor) using double as the type for AccountNumber, rather than long integer. From here on out, I will do a data conversion before I do the look up and that should take care of my problem.

Thanks!