Php pdo检查获取的结果集是否为空

For example:

$sql = 'select a, b, c from table where condition';
$stmt->prepare($sql);
$stmt->execute();
$data = $stmt->fetch();

AND

 $sql = 'select a, b, c from table where condition';
 $stmt->prepare($sql);
 $stmt->execute();
 $data = $stmt->fetchAll();

How to check if result set is empty or not

Check $data variable like:

if ($data) {
  //not empty
} else {
  // empty
}

if result of select query did not consist any data variable $data will consist null value.