I can think of a bunch of songs that have spawned many covers... sometimes too many. But which song has had the most covers / versions (including the original, if it charted) that have themselves hit the charts ? (These could be straight covers, or lyrical re-workings).
Yesterday - The Beatles
Yesterday is one of the most recorded songs in the history of popular music; its entry in Guinness World Records states that, by January 1986, 1,600 cover versions had been made.
The song has been covered by an eclectic mix of artists including Cilla Black, Aretha Franklin, Marianne Faithfull, Tose Proeski, The Mamas and the Papas, Barry McGuire, the Seekers, Joan Baez, Donny Hathaway, Michael Bolton, Royce Campbell, Bob Dylan, Liberace, Bill Champlin, Frank Sinatra, Matt Monro, Elvis Presley, Ray Charles, Marvin Gaye, Daffy Duck, Jan & Dean, the Sylvers, Wet Wet Wet, P. P. Arnold, Plácido Domingo, The Head Shop, Billy Dean, Wing, En Vogue, LeAnn Rimes, Muslim Magomayev, Andy Williams, and Boyz II Men.
The trouble is, I can't find a list of chart positions for these covers, so this remains speculation.
I think Shocking Blue - Venus. It's been covered a number of times successfully:
- Stockley Sisters (1976)
- Yōko Nagayama (1986)
- Bananarama (1986)
- Seduced (2004)
Arguably, the two most famous are the original and the Banarama cover.
'Unchained Melody' seems a potential winner with the following UK chart successes
- Jimmy Young (1955)
- Al Hibbler (1955)
- Les Baxter (1955)
- Liberace (1955)
- Righteous Brothers (1965 & 1990)
- Robson & Jerome (1995)
- Gareth Gates (2002)
and, as can be seen from the above linked Wiki page, a raft of other successful versions (notably appearing on US genre charts).
However, 'Everlasting Love' at least matches 'Unchained Melody' in terms of UK hit versions
- Love Affair (1968)
- Robert Knight (1968 and 1974)
- Rex Smith & Rachel Sweet (1981)
- Worlds Apart (1993)
- Gloria Estefan (1995)
- The Cast From Casualty (1998)
- Jamie Cullum (2004)
and also had a string of US successes, not least by Carl Carlton (1974) reaching the Billboard Hot 100 top 10.
Although Yesterday is indubitably the most recorded song, I haven't seen any evidence that it has hit the charts multiple times, perhaps because the original version is so definitive.
Blue Moon, however, according to its Wikipedia article, has hit the US charts at least four separate times, in very different versions (as well as having additional iconic versions, such as the one by Elvis, that didn't chart), reaching #1 in the Marcels' version. An additional version charted in Canada.
The Loco-Motion hit #1 twice and by Little Eva and then Grand Funk Railroad and then hit #3 by Kylie Minogue. For big hits charting multiple times I do not know of any more successful cover versions of any song.