dataset designer relation and crystal report

Question

I am using datables in dataset.xsd designer visual studio 2012. I have three tables

tblA,tblB and tblC

tblA (parent)   --- ---->  tblB
aid                       bid

tblB(parent)    -- ---->  tblC
nid                     nid

if tblB is empty then no data is displaying in report.I want to show data in report if no data is in datable B.