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Home > Backend Development > PHP Tutorial > PHP code using mysql_data_seek to move the pointer to the initial position of the data set

PHP code using mysql_data_seek to move the pointer to the initial position of the data set

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Release： 2016-07-25 09:03:34
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  2. // Start snipit 1
  3. $sql = "SELECT * from ";
  4. $result = mysql_query($sql);
  5. while ($row = mysql_fetch_assoc($result)) {
  6. // do stuff with $row
  7. }
  8. mysql_data_seek($result, 0); //The key is here
  9. while ($row = mysql_fetch_assoc($result)) {
  10. // do other stuff with $row
  11. }
  12. ?>
    13. Copy code

    Definition and usage

    mysql_data_seek() function moves the pointer of the internal result.

    Grammar mysql_data_seek(data,row) parameter description data required. Returns a result set of type resource. This result set is obtained from a call to mysql_query(). row required. The number of rows in the new result set pointer you want to set. 0 indicates the first record.

    Instructions mysql_data_seek() moves the row pointer within the MySQL result specified by the data parameter to the specified row number. A subsequent call to mysql_fetch_row() will return that row. row starts from 0. The value range of row should be from 0 to mysql_num_rows - 1. But if the result set is empty (mysql_num_rows() == 0), moving the pointer to 0 will fail with an E_WARNING level error, and mysql_data_seek() will return false.

    Return value Returns true if successful, false if failed.

    Tips and Notes Note: mysql_data_seek() can only be used with mysql_query(), not mysql_unbuffered_query().

    3. $con = mysql_connect("localhost", "hello", "321");
    4. if (!$con)
    5. {
    6. die('Could not connect: ' . mysql_error( ));
    7. }
    8. $db_selected = mysql_select_db("test_db",$con);
    9. $sql = "SELECT * from Person";
    10. $result = mysql_query($sql,$con);
    11. print_r(mysql_fetch_row($result ); Array ( [0] => Adams [1] => John [2] => London )
    13. Array ( [0] => Carter [1] => Thomas [2] => Beijing )

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