SUBSTRING filter on Projection

Hi Guys,

I am new to HANA and tried searching through forums but couldn't find a similar question so i thought I would ask the experts here.

This is what is needed : I have a view on COEP and COBK tables and all I want is only show values for when OBJNR = 'K'. when i write a SQL statement in SQL console to test using this:

select top 10 * from "_SYS_BIC"/MY_COVP_VIEW" where "GJAHR" = '2014' and "PERIO" = '002' and substring("OBJNR",1,1) = 'K'

this returns what I want, But when i try to put in the a filter in my Projection node (graphical view) on the column OBJNR, saying substring("OBJNR",1,1) = 'K', it returns an error during activation so this is definitely not the right way of doing this filter.

Will appreciate your time and help.

Thanks.