如何在PHP中获取SQL查询

Question

如何通过$ sql和$ sqll一起回显数据，任何人都可以解决此问题

$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

与其合并两个结果，不如只查询单个查询中的所有相关行，可能会更好：

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

Answer 2

只需将分号放在另一个查询之后，这样它将在单个查询中返回所有行。

像那样。

1个选项->

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

2个选项-> with in Operater（以下SQL语句选择13,15中用户标识的所有行）更多信息，请参见此处https://www.w3schools.com/sql/sql_in.asp

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

Answer 3

您有两个查询，即

SELECT chat_msg, chat_date FROM chat WHERE chat_room_id = '13' AND userid = '13'
SELECT chat_msg, chat_date FROM chat WHERE chat_room_id = '13' AND userid = '15'

尽管此查询可以正常运行，但可以按以下方式进行优化：

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

除了两个单独的查询，您只能使用一个查询来满足您的需求。

因此，打印查询所面临的问题也将得到解决，查询也将得到优化。

Answer 4

您还可以使用：-

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