why does this works: let name = "'A 20'" bd_rows <- query_ conn "select `N° BD` from sidonie.Coordonnées where Nom = 'A 20'" putStrLn $ show bd_rows putStrLn $ show name i got: [Only {fromOnly = "-04.3982"}] "'A 20'" -04.3982 but not with this: bd_rows <- query conn "select `N° BD` from sidonie.Coordonnées where Nom = ?" (Only (name::String)) i got an empty result: [] ... ??? -- Damien.Mattei@unice.fr, Damien.Mattei@oca.eu, UNS / OCA / CNRS