Ajax：从数据库中获取最后一行

Question

Is it possible to get the last row from MySql database using Ajax?

So this is my PHP:

<?php 
  include('../../dbconn.php');
  //--------------------------------------------------------------------------
  // Example php script for fetching data from mysql database
  //--------------------------------------------------------------------------
  $databaseName = "test";
  $tableName = "generalTransactions";

  //--------------------------------------------------------------------------
  // 1) Connect to mysql database
  //--------------------------------------------------------------------------

  $con = mysql_connect($gaSql['server'],$gaSql['user'],$gaSql['password']);
  $dbs = mysql_select_db($databaseName, $con);
  //--------------------------------------------------------------------------
  // 2) Query database for data
  //--------------------------------------------------------------------------

  $result = mysql_query("SELECT * FROM $tableName");          //query
  $array = mysql_fetch_row($result);                          //fetch result                          
  //--------------------------------------------------------------------------
  // 3) echo result as json 
  //--------------------------------------------------------------------------
  echo json_encode($array);

?>

This is the Ajax:

$(function () 
  {
    //-----------------------------------------------------------------------
    // 2) Send a http request with AJAX http://api.jquery.com/jQuery.ajax/
    //-----------------------------------------------------------------------
    $.ajax({                                      
      url: 'general/transactions/add-journal.php',                  //the script to call to get data          
      data: '',                        //you can insert url argumnets here to pass to api.php
                                       //for example "id=5&parent=6"
      dataType: 'json',                //data format      
      success: function(data)          //on recieve of reply
      {
        var id = data[0];
        var prefix = data[1];                //get prefix
        var journalNum = data[2];            //get journal number 
        //--------------------------------------------------------------------
        // 3) Update html content
        //--------------------------------------------------------------------
        //recommend reading up on jquery selectors they are awesome 
        // http://api.jquery.com/category/selectors/
        if(!journalNum){
            $('#generalJournalNumber').val('GJ00000001');
        }
        id++;
        $('#generalJournalNumber').val(prefix+'0000000'+id);
      } 
    });
  }); 

So basically I want to get the last id and auto increment it, the above only increments the first row in the database.

Any help or suggestions, will be appreciated!

Answer 1

Just add an order by descending on your primary key and limit it to only the first result:

SELECT * FROM TableName ORDER BY TableId DESC LIMIT 1