string s = "sg.department = '54b906d6-5c27-4c06-89c4-0b4a36cd8160";
            Regex reg = new Regex(@"\S*\s*=");
            Match m = reg.Match(s);
            MessageBox.Show(m.Value);

------解决方案--------------------
Replace("'54b906d6-5c27-4c06-89c4-0b4a36cd8160", "")

------解决方案--------------------
Regex.Matches()更适合

------解决方案--------------------
探讨


Replace("'54b906d6-5c27-4c06-89c4-0b4a36cd8160", "")