what about:

select distinct to a temp table

truncate source table

get the temp table data back in

or

select distinct from a to b

drop a

rename b to a

?

there is no info about the size of the table, concurrency requirements or if it's a 24x7 environment (or not) ... (so again standard dba reply "it depends" ...

*edit: sorry, now i see it's not a dedupe, somehow i missed such a simple point ...