How to change xamarin forms special character?

sql = @" UPDATE Customer SET customer_normalized= ( (SELECT lower(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace( membercode|| ' ' || membername, ?, 'u'), ?, 'c'), ?, 'i'), ?, 'o'), ?, 's'), ?, 'g'), ?, 'u'), ?, 'c'), ?, 'i'), ?, 'o'), ?, 's'), ?, 'g')) FROM Member WHERE _key = Customer._key_member) || lower(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(' ' || no || ' ' || strftime('%d-%m-%Y', date) || ' ' || total || ' ' || docno || ' ' || subject1 || ' ' || subject2 || ' ' || subject3, ?, 'u'), ?, 'c'), ?, 'i'), ?, 'o'), ?, 's'), ?, 'g'), ?, 'u'), ?, 'c'), ?, 'i'), ?, 'o'), ?, 's'), ?, 'g')) ) "

await DBHandler.ExecuteAsync(sql, "Ü", "Ç", "İ", "Ö", "Ş", "Ğ", "ü", "ç", "ı", "ö", "ş", "ğ", "Ü", "Ç", "İ", "Ö", "Ş", "Ğ", "ü", "ç", "ı", "ö", "ş", "ğ");

I used UTF8 ,but Turkish character don't use xamarin sqlite execute method. For example, I want to change from 'Ü' to 'u' character in database column.