question: public static String generateAssignmentFields ( String [ ] fields , String separator ) { String [ ] fieldAssignment = new String [ fields . length ] ; for ( int i = 0 ; i < fields . length ; i ++ ) { fieldAssignment [ i ] = "`" + fields [ i ] + "`=?" ; } return String . join ( separator , fieldAssignment ) ; }
target:  generate assignment fields string: `a`=?, `b`=? or `a`=? AND `b`=?