ERROR [HY000] [DataDirect][ODBC Progress OpenEdge Wire Protocol driver][OPENEDGE]Invalid date string (7497) (pgoe1022.dll)

Question

I am selecting data from a Progress database using the Data Direct Open Edge 10.1.B driver. The target table stores the date values as varchar in this format "22-OCT-14" In the select statement I can use Progress statements or T-SQL to transform
the varchar to a date - but cannot do the same in the WHERE clause 
Select po_number, cast(po_date as date) as [po_date] from [po_table] 
(no problem - the [po_date] field stored as "22-OCT-14" is returned as "2014-10-22 00:00:00"
but when I include the cast in the where clause I get the error described in the title
Select [po_number], [po_date] from [po_table WHERE cast([po_date] as date)<= '10/22/2014' - NO GOOD
I have tried very many combinations of the date string format , different functions and sub-queries but cannot find an answer

Answer 1

The sql strings I posted are working examples - I've tried the ISO format you included - any number of date formats will work when the target field is a "Date" field - but trying any kind of transform statment to processa date stored
as a varchar in the WHERE CLAUSE throws the erro
Storing dates in a varchar column is a bad idea on any platform. Apparently there are strings in that column which cannot be converted to dates.
On SQL Server you could have found this with
SELECT po_date FROM po_table WHERE isdate(po_date) = 1
What you should use on Progress, I have no idea.
Erland Sommarskog, SQL Server MVP, [email protected]