If i use eval() method in query it can,t give proper result because some value are null or empty?

[Pugazharasan Thirumalai]

If i use eval() method in query it can give proper result because some value are null or empty,

Is there  any possible way to overcome this problem.

Thanks and Regards,

T.Pugazharasan.

[Oleksandr Gubchenko]

Make your function/query do eval only if the value is not null.