php - 如何在php中进行sql查询

Question

如何通过 $sql 和 $sqll 一起回显数据，任何人都可以解决这个问题

$sql = "SELECT chat_msg, chat_date FROM chat WHERE chat_room_id = '13' AND userid = '13'";
$sqll = "SELECT chat_msg, chat_date FROM chat WHERE chat_room_id = '13' AND userid = '15'";
$result = $conn->query($sql);
$resultt = $conn->query($sqll);
if ($result->num_rows > 0 && $resultt->num_rows > 0){
    // output data of each row
    while($row = $result->fetch_assoc() && $roww = $resultt->fetch_assoc()) {
        echo "NO" . $row["chat_msg"]. $roww["chat_msg"].  "<br>";
    }
} else {
    echo "0 results";
}

Answer 1

您最好不要合并两个结果，而是在单个查询中查询所有相关行:

$sql = 
"SELECT chat_msg, chat_date FROM chat WHERE chat_room_id = '13' AND userid IN ('13', '15')";