Sapscript command is not working

H experts ,

I have put one command if &LV_NETWO_DISP& GE '0' in my script .

But this is not working , right now the value of &LV_NETWO_DISP& is -7.28 , but it still gose inside the if condition .

ideally it should come out of the if condition .

plz let me know how to compare the zero , negative and null values in sapscript?

Thanks is advance ,

sweetu..