select recent purchases from multiple mysql tables

So, I have 4 tables products1, products2, products3, products4 those all are tables containing products, so I need to select all those tables and sort them by recent purchases by latest date

I currently have the code only for one table, but I need to select all tables

    echo '<li>'.$row['product'].'  <font size="1" face="Tahoma" color="#CCC">at price</font> $'.$row['price'].'</li>';      }

Any help would highly be appreciated!

Source: stackoverflow-php