Quote Originally Posted by davey23uk View Post
coalesce isnt DDL

have a read of the concepts guide
I have also read the Course books by Oracle. Probably, I didn't find anywhere that 'alter index ... coalesce' is not a DDL.

But it does say that alter statement is a DDL and if 'coalesce' is not a DDL, then it is not mentioned anywhere there. Though, it's a good learn this thing.