Question

这里有人知道如何加入2个桌子吗？我在语法方面一直有错误我不知道错误是什么以及在哪里。我想要的只是从不同的表中获取这些特定数据。请帮助！

<?php
echo"<ul>";
$sql="select product_title.products, qty.cart from  products Inner Join cart on product_id.procucts=p_id.cart ";

$query = mysql_query($sql);

while($row = mysql_fetch_array($query))
    echo"
    <center>Summary of orders <br><br>
        <li>Your Order: $row[0]</li>
        <li>Quantity: $row[1]</li>
    </center><br/>";
echo"</ul>";
?>

Answer 1

表首先应该是第一个。因此，您的查询将如下所示：

1 2 3 4 Count: 0

Answer 2

这是第一个答案的解释（由KinjaMistry）。

你必须始终是代码语法！您必须始终以大写形式编写保留的SQL字。您必须始终格式化代码。这样可以避免将来出现此类问题和错误。

SELECT
        cart.qty,
        products.product_title
    FROM cart /* select first from cart beacause here cart is "parent" data */
    INNER JOIN products /* join "dependency" data */
        ON products.product_id = cart.p_id /* compare as dependency<->parent (like native: you<-above->friend) */

Answer 3

当你select＆amp; join clause table列名称table name。它应该首先显示$sql = "SELECT products.product_title, cart.qty FROM products INNER JOIN cart ON products.product_id = cart.p_id";而不是列名。

join

有关public interface ISaveData { void DeleteFile(); // this is common method } public interface IPermission { void AssignPermission(); } public interface IBucketOperation //or something else { void ChangeBucket(); } public class AzureSaveData : ISaveData, IBucketOperation { public void ChangeBucket() { Console.WriteLine("AzureSaveData ChangeBucket"); } public void DeleteFile() { Console.WriteLine("AzureSaveData DeleteFile"); } } public class GoogleCloudSaveFile : ISaveData, IPermission { public void AssignPermission() { Console.WriteLine("GoogleCloudSaveFile AssignPermission"); } public void DeleteFile() { Console.WriteLine("GoogleCloudSaveFile DeleteFile"); } }的更多信息： MySQL join

如何从2个表中检索数据？

3 个答案: