Python select_analysis where clause for numeric field

[PitersonPaulgek]

Hi,

I get error "Invalid expression" for:

where_clause ='"Yr" IS NULL'
arcpy.Select_analysis(InFC, OutFC, where_clause)

What is the correct syntax?

[PitersonPaulgek]

Fortunatelly, I run the simple test (Delete and Select) - it worked in ModelBuilder and then exported to PythonScript with syntax : 

arcpy.Select_analysis(in_features,out_features, "Yr IS NOT NULL")

Thanks for help!!!