Null Value in Expression, but not from script?

[#1]

I have two tables, Table A and Table B

Table A contains diag_code

Table B Contains diag_code

Table B Contains diag_desc

These codes are used for Diagnostic codes and Non Diagnostic codes.

If table A diag_code = table B diag_code, table B diag_desc is valid and has a value.(Diagnostic)

If Table A diag_code <> Table B diag_code, Table B diag_desc has no value, but it is not null!!!! (Non Diagnostic)

If I do an inner join between A and B on diag_code, then I get the correct values for Diagnostic codes.

.

My problem comes when I try to get just the Non Diagnostic values to show. They show as a null value in a chart, but not from the script.

If I do an outer join, they all show, but I cannot seem to be able to get just the ones where the diag_desc is null/no value relating to the diag_code

diag_code	diag_desc
H221	Diagnostic fibreoptic endoscopic examination of colon and biopsy of lesion of colon
W371	-

H221 is Diagnostic and W371 is Non Diagnostic.

How do I get just the non to show, or how do I get a selection box to show Diagnostic and Non Diagnostic as I cannot get diag_desc to show as a null?

Thanks

[#2 · Accepted solution]

Hi,

Here you are a possible solution.

Best regards.

[#3]

Hi,

Thank-you very much.

This is exactly what I wanted. 🙂