private StringBuilder genDistinctFilterSql(List<FieldInfo> fields, StringBuilder sb) {
        String subSql = sb.toString();
        sb = new StringBuilder("SELECT ");
        for (FieldInfo field : fields) {
            sb.append("\n    `").append(field.getName()).append("`,");
        }
        sb.deleteCharAt(sb.length() - 1).append("\n    FROM (").append(subSql)
                .append(")\nWHERE row_num = 1");
        return sb;
    }
Generate filter sql of distinct node

@param fields The fields of node
@param sb Container for storing sql
@return A new container for storing sql
inlong-sort/sort-core/src/main/java/org/apache/inlong/sort/parser/impl/FlinkSqlParser.java