Max says, but if the structure does not change, can not stand such operations on the client - very will shrink in speed.
Make a view that unites all tables with the minimum data as required and sort by date.
Description is added like this:
select date, price, 'table 1' as desc from table1
select date, price, 'table 2' as desc from table2
select date, price, 'table 3' as desc from table3
Make it a view and sort as you like