如何动态计算数据库中的行数？
[英]How to count the number of rows in database dynamically?
问题描述
The php code below is a simple way to count number of rows in a certain table, but any increase or decrease in rows can only be noticed when page is refreshed. 
下面的php代码是一种计算特定表中行数的简单方法，但是只有刷新页面时，才能注意到行的任何增加或减少。 So is there any way using jQuery/ajax which can show the number of rows in database table dynamically without refreshing the page and without any click function. 因此，有什么方法可以使用jQuery / ajax来动态显示数据库表中的行数，而无需刷新页面和任何单击功能。
html.php html.php
$sql=$db->prepare("SELECT * FROM table WHERE selector=:selector");
$sql->execute(array(':selector'=>$selector));
$count=$sql->rowCount();
echo $count;
2 个解决方案
解决方案1
2 已采纳 2016-03-03 06:15:00
count.php count.php
$sql=$db->prepare("SELECT * FROM table WHERE selector=:selector");
$sql->execute(array(':selector'=>$selector));
$count=$sql->rowCount();
$arr = array('count' => $count)
echo json_encode($arr);
Add following script to you index file 将以下脚本添加到索引文件
<script>
$(document).ready(function() {
setInterval("ajaxcall()",2000);
});
function ajaxcall() {
$.ajax({
type: "GET",
url: "count.php"
success: function(response){
json_object = JSON.parse(response)
var count = json_object.count
/// set this count variable in element where you want to
/// display count
}
});
}
</script>
If you don't want to use Jquery than you can try : 如果您不想使用Jquery，则可以尝试：
function ajaxcall() {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (xhttp.readyState == 4 && xhttp.status == 200) {
json_object = JSON.parse(xhttp.responseText)
var count = json_object.count
/// set this count variable in element where you want to
/// display count
}
};
xhttp.open("GET", "count.php", true);
xhttp.send();
setTimeout(ajaxcall, 1000)
}
</script>
And add onload event on your body tag 并在您的body标签上添加onload事件
<body onload="setTimeout(ajaxcall, 3000)" >
or you can call ajax on some button click 或者您可以通过单击某些按钮来调用ajax
<button onclick="setTimeout(ajaxcall, 3000)">clickme</button>
解决方案2
1 2016-03-03 05:55:03
Try to make the sql query in a php function which is accessible through an url and returns json_encoded(num_of_rows). 尝试在可通过url访问并返回json_encoded（num_of_rows）的php函数中进行sql查询。 Then in your javascript you can get it through an ajax get request, specifying it is json, better to set in a function which is a onClick event on a button, which you will click to make the call without refreshing the pages, but just the target tag where your javascript function will put the result from the ajax. 然后在您的javascript中，您可以通过ajax get请求将其获取，将其指定为json，最好在一个按钮上设置onClick事件的函数中进行设置，您无需单击即可单击以进行调用，而无需刷新页面，但是target标记，您的javascript函数会将结果从ajax中放入。 Hope it is clear enough. 希望它足够清楚。
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