is it better to use join?

hi

i want to select header details from LIKP and item details from LIPS. i have VBELN number with me. now there are two scenarios

in first one

i can use select single to get the header details

then chekc sy-subrc to make sure that document exists in the system then query LIPS to get the item details.

second case

use join between LIKP and LIPS join on VBELN.

what would be the best in terms of performance in case if u want to select only one item from LIPS?