用sql表格繪製Google圖表

Question

我用谷歌圖譜在sql表格中繪製了一個變量圖，下面是我的代碼，就像你看到它用最後一行繪製圖表一樣，如何繪製最後一行3 ？我知道我應該使用DESC LIMIT 3但是如何？

<?php 
    $result = mysql_query("SELECT * FROM result ORDER BY id DESC LIMIT 1"); 
    $value=array(); 
    while($r = mysql_fetch_assoc($result)) { 
     $year=$r['year']; 
     $sales=$r['sales']; 
     $expenses=$r['expenses']; 
     $val="[".$year.",".$sales.",".$expenses."]"; 
     array_push($value,$val); 
    } 
    $final_value = implode(",", $value); 
?> 

function drawChart() { 
    var data = google.visualization.arrayToDataTable([ 
     <?php echo $final_value?> 
    ]); 

    var options = { 
     title: 'Company Performance' 
    }; 

    var chart = new google.visualization.LineChart(document.getElementById('chart_div')); 
    chart.draw(data, options); 
} 

Answer 1

這是真的嗎？你已經知道答案！

SELECT * FROM result ORDER BY id DESC LIMIT 1 

改變，要

SELECT * FROM result ORDER BY id DESC LIMIT 3 

???