使用 PHP 检查 SQL 行是否存在

问题描述：

我在 PHP 中使用 MySQL，我需要做这样的事情(伪代码):

I'm using MySQL with PHP and I need to do something like this (pseudocode):

if (sql row exists where username='bob')
{
    // do this stuff
}

答

如果你使用的是mysql数据库，那么使用下面的-

If you are using mysql database, then use the following -

$query = "SELECT username from my_table where username='bob'";
$result = mysql_query($query);

if(mysql_num_rows($result) > 0)
{
    // row exists. do whatever you would like to do.
}

如果您想使用 PDO(PHP 数据对象)，按照亚历克斯的建议，然后使用以下代码 -

If you would like to use PDO (PHP Data Object), as alex suggested, then use the following code -

$dbh = new PDO("mysql:host=your_host_name;dbname=your_db_name", $user, $pass);
$stmt = $dbh->prepare("SELECT username from my_table where username = ':name'");
$stmt->bindParam(":name", "bob");
$stmt->execute();

if($stmt->rowCount() > 0)
{
    // row exists. do whatever you want to do.
}

使用 PHP 检查 SQL 行是否存在

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