transpose rows into columns

[MRTREE]

What is the best way to flip a table into database form?

table looks like this:
item group month1 month2 month3
123 abc 1000 2000 3000
789 abc 500 600 700

to this:
item group month qty
123 abc month1 1000
123 abc month2 2000
123 abc month3 3000
789 xyz month1 500
789 xyz month2 600
789 xyz month3 700

Can I do it an eaiser way other than 1 make table
followed by 5 append queries?

thanks....