MySQL加入表列

Question

我是一个非常新的人，我需要一些帮助。

    <?php
        $query = "SELECT owners_dogs.dog_id, dog.name, FROM owners_dogs 
        LEFT JOIN dog ON owners_dogs.dog_id = dog.id WHERE owners_dogs.person_id=$currId ORDER BY dog.name;";
        $result = mysql_query($query) or die('Query failed: ' . mysql_error());
        if (mysql_num_rows($result)>0) {    
            echo "<i>Owner of: </i>";
            echo "<div style='padding-left:25px;padding-bottom:10px;'>";
            while ($line = mysql_fetch_object($result)) {
                echo "<a href='details.php?id=$line->dog_id'>";
                echo "$line->name </a><? if(dog.certfied == '1') echo "CP" ?><br>";
            }
            echo "</div>";
        }
    ?>

我遗漏了一些东西......如果dog.certified = 1，我正试图让脚本回显一些文字

非常感谢任何帮助

Answer 1

我发现了两个可能的错误 1.要使用certfied的值进行比较，您应首先在查询中获取该数据 2.您不能在while循环中直接使用dog.certfied，而是使用$line->certfied。

试试这个

$query = "SELECT owners_dogs.dog_id, dog.name, dog.certfied, FROM owners_dogs
    LEFT JOIN dog ON owners_dogs.dog_id = dog.id WHERE owners_dogs.person_id=$currId ORDER BY dog.name;";
$result = mysql_query($query) or die('Query failed: ' . mysql_error());
if (mysql_num_rows($result) >0 )
{
    echo "<i>Owner of: </i>";
    echo "<div style='padding-left:25px;padding-bottom:10px;'>";
    while ($line = mysql_fetch_object($result))
    {
        $dog_id = $line->dog_id;
        $name = $line->name;


        echo "<a href='details.php?id=".$dog_id."'>";
        echo $name."</a>";
        if($line->certfied == '1');
        {
            echo "CP"."<br>";
        }

    }
    echo "</div>";
}

Answer 2

试试这个

    $query = "SELECT owners_dogs.dog_id, dog.name, certified FROM owners_dogs
        LEFT JOIN dog ON owners_dogs.dog_id = dog.id WHERE owners_dogs.person_id=$currId ORDER BY dog.name;";
    $result = mysql_query($query) or die('Query failed: ' . mysql_error());
    if (mysql_num_rows($result) >0 )
    {
        echo "<i>Owner of: </i>";
        echo "<div style='padding-left:25px;padding-bottom:10px;'>";
        while ($line = mysql_fetch_object($result))
        {
            $dog_id = $line->dog_id;
            $name = $line->name;


            echo "<a href='details.php?id=".$dog_id."'>";
            echo $name."</a>";
            if($line->certfied == '1');
            {
                echo "CP"."<br>";
            }

        }
        echo "</div>";
    }

错误是

1. <? if(dog.certfied == '1')这里没有php执行
此处
2. echo "CP" ?><br>";错误
3. 在,
上删除dog.name, FROM
4. 在选择查询中缺少表格（certified）。

Answer 3

查询更改

在certified列表

中添加列SELECT

$query = "SELECT owners_dogs.dog_id, dog.name, certified FROM owners_dogs 
    LEFT JOIN dog ON owners_dogs.dog_id = dog.id 
    WHERE owners_dogs.person_id = $currId ORDER BY dog.name;";

如果列certified仅在一个表中，则此查询将起作用。否则，请将表别名添加到列certified

代码更改

echo '<a href="details.php?id=$line->dog_id">'.$line->name.'</a>';
echo ((strcmp($line->certfied, '1') == 0) ? "CP" : "")."<br>";

说明

我们在echo ((strcmp($line->certfied, '1') == 0) ? "CP" : "")."<br>";

中回显了两个字符串

1. ((strcmp($line->certfied, '1') == 0) ? "CP" : "")
2. "<br>";

在第一部分中，我们使用三元运算符，它由三部分组成

• condition？ true value：false value

它评估你的给定条件，如果它是真的，那么它返回true value其他明智的false value。现在我们的条件为(strcmp($line->certfied, '1') == 0)，即将$line->certified与1进行比较。如果两者相等，则strcmp返回0。因此，如果$line->certified == 1 "CP"将以其他方式返回空字符串

在第二部分中，我们只有一个字符串"<br>"

两个部分是连接的，结果字符串是echo ed

Answer 4

第1点：从第一行删除“，”

第2点：删除“;”从dog.name

之后的第二行开始

第3点：第echo "$line->name </a><? if(dog.certfied == '1') echo "CP" ?><br>";行     应该像echo "$line->name </a>"; if($line->certfied == '1') echo "CP <br>";

Here is the code with correction
<?php
    $query = "SELECT owners_dogs.dog_id, dog.name, dog.certfied FROM owners_dogs 
    LEFT JOIN dog ON owners_dogs.dog_id = dog.id WHERE owners_dogs.person_id=$currId ORDER BY dog.name";
    $result = mysql_query($query) or die('Query failed: ' . mysql_error());
    if (mysql_num_rows($result)>0) {    
        echo "<i>Owner of: </i>";
        echo "<div style='padding-left:25px;padding-bottom:10px;'>";
        while ($line = mysql_fetch_object($result)) {
            echo "<a href='details.php?id=$line->dog_id'>";
            echo "$line->name </a>"; if($line->certfied == '1') echo "CP <br>";
        }
        echo "</div>";
    }
?>