Java 好吧，Oracle查询它工作得很好，但PostgreSQL查询工作得不好。看起来问题出在查询上。 public List<CustomersObj> list(int firstRow, int rowCount, String sortFi

---

好吧，Oracle查询它工作得很好，但PostgreSQL查询工作得不好。看起来问题出在查询上。

 public List<CustomersObj> list(int firstRow, int rowCount, String sortField, boolean sortAscending) throws SQLException
        {

            String SqlStatement = null;

            if (ds == null)
            {
                throw new SQLException();
            }

            Connection conn = ds.getConnection();
            if (conn == null)
            {
                throw new SQLException();
            }

            int countrow = firstRow + rowCount;
            String sortDirection = sortAscending ? "ASC" : "DESC";

// Oracle
    //        SqlStatement = "SELECT A.* "
    //            + " FROM (SELECT B.*, ROWNUM RN "
    //            + " FROM (SELECT Y.COMPONENTSTATSID, Y.NAME, Y.SERIALNUMBER, Y.WEIGHTKG, Y.ZONECAGE, Y.POWERWATT, Y.MANIFACTURECOMPANY, Y.UFORM, "
    //            + " Y.STATUS, Y.LOCATION, Y.HEATEMISIONSBTU, Y.PRODUCTIONENVIRONMENT, Y.STANDARTLIFETIME, Y.OPERATINGHAMIDITYRANGE, "
    //            + " Y.OPERATINGSYSTEM, Y.DATEDEPLOYED, Y.INTERFACETYPE, Y.TYPE, Y.COOLINGCAPACITYBTU, Y.DATEADDED, Y.DESCRIPTION "
    //            + " FROM COMPONENTWEIGHT X, COMPONENTSTATS Y WHERE X.COMPONENTSTATSID = Y.COMPONENTSTATSID AND Y.COMPONENTTYPEID = 3300 "
    //            + " ORDER BY %S %S) B "
    //            + " WHERE ROWNUM <= ?) A "
    //            + " WHERE RN > ?";
// postgresql
            SqlStatement = "SELECT * FROM CUSTOMERS ORDER BY %S %S offset ? limit ? ";

            String sql = String.format(SqlStatement, sortField, sortDirection);

            PreparedStatement ps = null;
            ResultSet resultSet = null;
            List<CustomersObj> resultList = new ArrayList<>();

            try
            {
                conn.setAutoCommit(false);
                boolean committed = false;

                ps = conn.prepareStatement(sql);
                ps.setInt(1, countrow);
                ps.setInt(2, firstRow);

                resultSet = ps.executeQuery();
                resultList = ProcessorArrayList(resultSet);

                conn.commit();
                committed = true;

            }
            finally
            {
                ps.close();
                conn.close();
            }

            return resultList;
        }

LIMIT { count | ALL } OFFSET start

int countrow = firstRow + rowCount;

            ps.setInt(1, countrow);
            ps.setInt(2, firstRow);

            ps.setInt(1, firstRow - 1);
            ps.setInt(2, rowCount);

 int countrow = firstRow + rowCount;
 SqlStatement = "SELECT * FROM CUSTOMERS ORDER BY %S %S offset ? limit ? ";
 ps = conn.prepareStatement(sql);
 ps.setInt(1, countrow);
 ps.setInt(2, firstRow);

  To retrieve the first page -> `LIMIT 50 OFFSET 0` [rows 0 to 49]

  To retrieve the second page -> `LIMIT 50 OFFSET 50` [rows 50 to 99] 

  ...

  To retrieve the nth page -> `LIMIT 50 OFFSET (n - 1)*50`

 ps.setInt(1, firstRow);  // Assign firstRow to OFFSET
 ps.setInt(2, rowCount);  // Assign rowCount to LIMIT

  YES ->  ps.setInt(1, firstRow);
  NO  ->  ps.setInt(1, firstRow - 1);