javadb2-zos

javax - executeQuery() - DB2 z/OS ERRORCODE=-4476, SQLSTATE=02501 - COUNT(...)

I get the following error:

com.ibm.db2.jcc.am.SqlException: [jcc][t4][1090][10899][4.32.28] Invalid operation to read at current cursor position. ERRORCODE=-4476, SQLSTATE=02501

running the following "query":

final String sql = "SELECT COUNT(A1.ID) AS C1 FROM MY_SCHEMA.MY_TABLE A1 ";
try (final Connection connection = dataSource.getConnection();
    final Statement statement = connection.createStatement();
    final ResultSet resultSet = statement.executeQuery(sql)) {
  Long count = resultSet.getObject(1, Long.class);
} catch (Exception ex) {
  log.error("Error in query \"{}\"", sql, ex);
  throw new RuntimeException(ex.getMessage(), ex);
}

I tried to use * instead of ID, added semicolon in the end, no alias for table...

Solution

  • You need to use resultSet.next() like this:

    Long count = 0L;  
if (resultSet.next()) {
  count = resultSet.getObject(1, Long.class);
} 
...

    Or:

    Long count = resultSet.next() ? resultSet.getObject(1, Long.class) : 0L;

    resultSet.next(): Advances the cursor to the first row. Without this call, accessing the data in the ResultSet will throw an error.