CDate(IIF(isnull(SuppliedDate),'01/01/1990',SuppliedDate))
becomes
coalesce(SuppliedDate, '1900/01/01')
This returns supplied date, or the constant, if supplied date is null.
It seems you want to convert an int to a date. You can't do that in SQL Server. CDate also does not exist ( as I keep saying ). Here is a page listing possible conversions and if you need to make them explicit:
http://msdn.microsoft.com/en-us/library/ms187928.aspx[
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