Graphic of two tables

Graphic of two tables

I have two tables (Pendientes and Datos-Casos Cerrados). I want to show in the same graphic the amount of "casos" in each table by month. In the case of Pendientes it would be the date on "Fecha de Solicitud"  column and in Datos-Casos Cerrados the date of "Fecha Cierre" column.

I hope I make myself clear and you guys help me as soon as possible.

Thank