<Li> How Long Has This Been Going On? (Sarah Vaughan album), a 1978 album </Li> <Li> How Long Has This Been Going On (Van Morrison album), a 1996 album with Georgie Fame and Friends </Li> <Li> "How Long" (Ace song), 1974 </Li> <Li> "How Long" (Charlie Puth song), 2017 </Li>

Who sang how long has this been going on