static void appendColumns(StringBuilder s,String[] columns){
  for (int i=0; i < columns.length; i++) {
    if (i > 0) {
      s.append(", ");
    }
    s.append(StringUtils.quoteIdentifier(columns[i]));
  }
}

static void appendColumns ( StringBuilder s , String [ ] columns ) { for ( int i = 0 ; i < columns . length ; i ++ ) { if ( i > 0 ) { s . append ( ", " ) ; } s . append ( StringUtils . quoteIdentifier ( columns [ i ] ) ) ; } }
append the column to the string builder . the columns are separated by comma .
