Merge Two Worksheets ...

Is there any way that you can combine two worksheets or Excel files, for example:
WORKSHEET_1 has columns and values as:
firstname
lastname
city
state

WORKSHEET_2 has coulms with NO values as:
firstname
lastname
address
city
state phone

I want to take the info from WORKSHEET_1 and insert it into WORKSHEET_2 without specifying any columns since WORKSHEET_1 might sometimes have only 1 column and sometimes might have all 5 columns.

The purpose of this is to create a standardized Excel file that I need to import into a Database, however the users might have Excel files without all the columns required therefore I need to "standardize" the worksheet before being imported and have any black values import as NULL into the Database