从数据库中选择列等于变量中的任何值

Question

我的数据库如下所示：

我有一个看起来像这样的变量：

$following = "John, Sarah";

我想获取列＆＃39;用户名＆＃39;在变量$following中（在这种情况下，John和Sarah）。为此，我查看了答案https://stackoverflow.com/a/1356018/5798798，建议我在我的查询中使用IN，我尝试过：

$following = "John, Sarah";
$stmt = $con->prepare("SELECT * FROM events WHERE username IN ('$following')");
$stmt->execute();
while($row = $stmt->fetch()) {
   echo $row['eventtype'];
}

问题是查询没有返回任何数据。我想要的结果是：

  说话走了

Answer 1

From what I suggested in comments to use the following:

$following = "John, Sarah"; 
$following = explode(", ", $following); 
$string = implode(", ", $following); 

It ended up that I didn't include the quotes for the implode()'ing.

The final solution was to add the single quotes in the first parameter for the implode() function:

$following = implode("','",$following);

Answer 2

$following = join("', '", $following);

join不再返回数组。现在是一个字符串。

您可以使用Static class variables in Python：

$in  = str_repeat('?,', count($following ) - 1) . '?';
$stmt = $con->prepare("SELECT * FROM events WHERE username IN ($in)");
$stm->execute($following);

Answer 3

没有使用join你可以通过以下方式直接内爆数组

$stmt = $con->prepare('SELECT * FROM events WHERE username IN ("'. implode('","', $following).'")');
$stmt->execute();
while($row = $stmt->fetch()) {
   echo $row['eventtype'];
}

注意：$ follow总是应该在数组

中