You just need to write a query that combines the data of two table tables and show it as datasource of your grid.
There is other wya to retrieve both tables separately on front end and then combine - but I would not suggest this as it would be much easier to combine them at DB level.
t1.col1, t1.col2, t2.col3
ON t1.RegNO = t2.RegNO
Result set would have combined data that can directly be set as source for grid.