Php 使用内部联接问题复制数据

我正在构建一个项目，希望从三个不同的表中检索数据，所以我使用了内部连接，但刚刚发现它正在复制数据，下面是它目前正在做的事情

Name: Ian Haney
First Line of Address: 12C Barclays Bank Chambers
Second Line of Address: Broadway North
Town: Pitsea
County: Essex
Postcode: SS13 3AU
Telephone Number: 01268 206297
Mobile Number: 07538 503276
Car Model: Jeep
Car Number Plate: AB10 1AB
Insurance expiry date: 30 July 2015
Name: Ian Haney
First Line of Address: 12C Barclays Bank Chambers
Second Line of Address: Broadway North
Town: Pitsea
County: Essex
Postcode: SS13 3AU
Telephone Number: 01268 206297
Mobile Number: 07538 503276
Car Model: Jeep
Car Number Plate: AB10 1AB
Tax expiry date: 30 June 2015

我想要的是

Name: Ian Haney
First Line of Address: 12C Barclays Bank Chambers
Second Line of Address: Broadway North
Town: Pitsea
County: Essex
Postcode: SS13 3AU
Telephone Number: 01268 206297
Mobile Number: 07538 503276
Car Model: Jeep
Car Number Plate: AB10 1AB
Tax expiry date: 30 June 2015
Insurance expiry date: 30 July 2015
MOT expiry date: 30 August 2015

这可能吗

我的代码如下

<?php

if (logged_in() == false) {
    redirect_to("login.php");
} else {
    if (isset($_GET['id']) && $_GET['id'] != "") {
        $id = $_GET['id'];
    } else {
        $id = $_SESSION['user_id'];
    }

    ## connect mysql server
        $mysqli = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME);
        # check connection
        if ($mysqli->connect_errno) {
            echo "<p>MySQL error no {$mysqli->connect_errno} : {$mysqli->connect_error}</p>";
            exit();
        }

    ## connect mysql server
        $mysqli = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME);
        # check connection
        if ($mysqli->connect_errno) {
            echo "<p>MySQL error no {$mysqli->connect_errno} : {$mysqli->connect_error}</p>";
            exit();
        }
    ## query database
        # fetch data from mysql database

        $sql = "SELECT v.visitor_id, visitor_name, visitor_email, visitor_firstline, visitor_secondline, visitor_town, visitor_county, visitor_postcode, visitor_tel, visitor_mobile, visitor_model, visitor_plate, item.description, renewal_id, DATE_FORMAT(renewal_date, '%e %M %Y') as datedue, renewal_date FROM visitors v 
        INNER JOIN renewal USING (visitor_id)
        INNER JOIN item USING (item_id)
        WHERE renewal_date >NOW()";


        if ($result = $mysqli->query($sql)) {
            $user = $result->fetch_array();
            } else {
            echo "<p>MySQL error no {$mysqli->errno} : {$mysqli->error}</p>";
            exit();
            }

    if(mysqli_num_rows($result)) {  

   //fetch the data from the database 
while ($row = mysqli_fetch_array($result)) {

# echo the user profile data
            /*echo "<p>User ID: {$user['id']}</p>";*/
            echo "<p>Name: {$user['visitor_name']}</p>";
            echo "<p>First Line of Address: {$user['visitor_firstline']}</p>";
            echo "<p>Second Line of Address: {$user['visitor_secondline']}</p>";
            echo "<p>Town: {$user['visitor_town']}</p>";
            echo "<p>County: {$user['visitor_county']}</p>";
            echo "<p>Postcode: {$user['visitor_postcode']}</p>";
            echo "<p>Telephone Number: {$user['visitor_tel']}</p>";
            echo "<p>Mobile Number: {$user['visitor_mobile']}</p>";
            echo "<p>Car Model: {$user['visitor_model']}</p>";
            echo "<p>Car Number Plate: {$user['visitor_plate']}</p>";       
            echo "<p>" . $row['description'] . " expiry date: " . $row['datedue'] . "</p>\n";

}
        } else { // 0 = invalid user id
            echo "<p><b>Error:</b> Invalid user ID.</p>";
        }

}

?>

这需要工作：

SELECT v.visitor_id, visitor_name, visitor_email, visitor_firstline, visitor_secondline, visitor_town, visitor_county, visitor_postcode, visitor_tel, visitor_mobile, visitor_model, visitor_plate, item.description, renewal_id, DATE_FORMAT(renewal_date, '%e %M %Y') as datedue, renewal_date FROM visitors v 
            INNER JOIN renewal on (v.vistor_id = renewal.visitor_id)
            INNER JOIN item on (v.vistor_id = item.visitor_id)
            WHERE renewal_date >NOW()

链接3个表会导致性能下降。您需要先扭曲2个表，然后像这样连接第3个表：

select a.* from (
SELECT v.visitor_id, visitor_name, visitor_email, visitor_firstline, visitor_secondline, visitor_town, visitor_county, visitor_postcode, visitor_tel, visitor_mobile, visitor_model, visitor_plate, item.description, renewal_id, DATE_FORMAT(renewal_date, '%e %M %Y') as datedue, renewal_date FROM visitors v 
        INNER JOIN renewal on (v.vistor_id = renewal.visitor_id) ) as a
        INNER JOIN item on (a.vistor_id = item.visitor_id)
        WHERE renewal_date >NOW()

啊，好的，对不起，我有点困惑，是这样的吗

$sql = "SELECT a.* from (
SELECT v.visitor_id, visitor_name, visitor_email, visitor_firstline, visitor_secondline, visitor_town, visitor_county, visitor_postcode, visitor_tel, visitor_mobile, visitor_model, visitor_plate, item.description, renewal_id, DATE_FORMAT(renewal_date, '%e %M %Y') as datedue, renewal_date FROM visitors v 
        INNER JOIN renewal on (v.vistor_id = renewal.visitor_id) ) as a
        INNER JOIN item on (a.vistor_id = item.visitor_id)
        WHERE renewal_date >NOW()";

看起来像是内部联接问题，试着换成这样：从（table1.id=table2.id）上的table1内部联接table2中选择table1.id。您必须显示/解释您的表结构，但可能您正在执行“树”联接，而不是单个“分支”。当您执行联接时，输入表中匹配行的每个组合都会得到一行。你得到的是重复的，因为你在
续费
和/或
项目
中有多个匹配行。你还在
while
循环中使用
$user
，但它只包含第一行的数据。
作为一个
在
之前，而不是之后。我知道它是什么。我只是指出你的语法是错误的。它应该是
内部连接续订作为一个ON…
抱歉，我没有看到额外的括号。如果缩进与嵌套级别匹配，则会有所帮助。