UNION ALL
を使用できます
2つのクエリの結果をマージするには
$sql = "SELECT * FROM `0530-0605` WHERE SearchTerm = :yes
UNION ALL
SELECT * FROM `0606-0612` WHERE SearchTerm = :yes1";
$stmt = $conn->prepare($sql);
$stmt->bindParam(":yes", $yes);
$stmt->bindParam(":yes1", $yes);
$stmt->execute();
foreach($stmt as $row) {
$datay1[] = $row['Clicks'];
}