Advice on appending tables - remove columns before or after appending?

[ruthhacche]

I am appending three identically structured tables but only want a few columns from them.  

Which is the most effiicient:

• select the columns needed in each of the tables and then append
• append and then select the columns needed?

Or does it make no difference - in which case the second one cos less setps to create.

[mahoneypat · Accepted solution]

Both appending and column selection are performant steps, so go the easier way.  Only consider trying the other if it seems slow.

If this works for you, please mark it as the solution.  Kudos are appreciated too.  Please let me know if not.

Regards,

Pat