mysql_ *没有连接到数据库

Question

$con = mysql_connect("localhost","username","password","db name") or die('not connected'); 
echo "connected"; 

$sql = "SELECT id, first_name, last_name FROM reg-users"; 
$result = $conn->query($sql); 

if ($result->num_rows > 0) { 
// output data of each row 
    while($row = $result->fetch_assoc()) { 
     echo "id: " . $row["id"]. " - Name: " . $row["first_name"]. " " . $row["last_name"]. "<br>"; 
    } 
} 
else 
{ 
    echo "0 results"; 
} 

我已经使用了上面的代码。但不工作。 mysql选择查询不起作用。 请给我解决方案。

Answer 1

更改下面的代码行

$result = $conn->query($sql); 

与

$result = $con->query($sql); 

你有$ CON作为MySQL连接对象。

而且还尝试从http://www.tutorialspoint.com/

Answer 2

学习基本的选择查询执行的代码以下更改：

1. 替换mysql_connect（）函数来mysqli_connect（）
2. 更换线$结果= $ conn->查询（SQL $）;用$ result = $ con> query（$ sql）; < < - 请注意在$ CON拼写错误

你的代码应该是：

$con = mysqli_connect("localhost","username","password","db name") or die('not connected'); 
echo "connected"; 

$sql = "SELECT id, first_name, last_name FROM reg-users"; 
$result = $con->query($sql); // <<-- please note spelling mistake in $con 

if ($result->num_rows > 0) { 
// output data of each row 
    while($row = $result->fetch_assoc()) { 
     echo "id: " . $row["id"]. " - Name: " . $row["first_name"]. " " . $row["last_name"]. "<br>"; 
    } 
} 
else 
{ 
    echo "0 results"; 
}