MySql Select Command返回null(MySql Select Command returning null)

MySql Select Command返回null(MySql Select Command returning null)

我有一个简单的PHP代码，它将值输入MySql数据库，然后检索并显示它。 但是，在检索它时，它总是返回null，并且每次都会回显Empty Set。 有人可以请帮助。

我正在使用WAMP服务器。

数据库名称为试用版，表名为People。 它有2个属性：名称和电子邮件ID

以下是我的代码：

$con=mysqli_connect("localhost","root",""); if (mysqli_connect_errno()) echo "Failed to connect to MySQL: " . mysqli_connect_error(); mysqli_query($con,"INSERT INTO People VALUES ('xyz', 'abc@zzz.com')"); echo "Insertion Success"; $result = mysqli_query($con,"SELECT * FROM People"); if($result == null) echo "Empty Set"; else while($row = mysqli_fetch_array($result)) { echo $row['name'] . " " . $row['emailid']; echo "<br>"; } mysqli_close($con); ?>

I have a simple php code which enters value into MySql database and then retrieves it and displays it. However when retrieving it always return null and Empty Set is echoed everytime. Can someone please help.

I am using WAMP Server.

Database name is trial and name of table is People. It has 2 attributes: name and email id

Following is my code:

$con=mysqli_connect("localhost","root",""); if (mysqli_connect_errno()) echo "Failed to connect to MySQL: " . mysqli_connect_error(); mysqli_query($con,"INSERT INTO People VALUES ('xyz', 'abc@zzz.com')"); echo "Insertion Success"; $result = mysqli_query($con,"SELECT * FROM People"); if($result == null) echo "Empty Set"; else while($row = mysqli_fetch_array($result)) { echo $row['name'] . " " . $row['emailid']; echo "<br>"; } mysqli_close($con); ?>

最满意答案

您应该在使用mysqli_connect但在完成任何查询之前选择一个数据库：

$con=mysqli_connect("localhost","root",""); if (mysqli_connect_errno()) echo "Failed to connect to MySQL: " . mysqli_connect_error(); mysqli_select_db($con, "databasename"); //query processing here..

You should select a database after using mysqli_connect but before any queries are done:

$con=mysqli_connect("localhost","root",""); if (mysqli_connect_errno()) echo "Failed to connect to MySQL: " . mysqli_connect_error(); mysqli_select_db($con, "databasename"); //query processing here..