如何从多个数据库中获取数据到表中


How fetch data from multiple database into tables

我关心在我的代码中找到错误。我尝试过其他代码,但错误不断出现。我所要做的就是将选中的数据检索到表中。请帮助!

<?php
echo"<table>";
$sql="select products.product_title,orders.order_id,products.product_price, cart.qty from products, cart where products.product_id=cart.p_id";
$query = mysql_query($sql);
while($row = mysql_fetch_array($query)){ 
    echo "<tr>"; 
    echo "<td>"."<center>" .$row[0]."</td>"; 
    echo "<td>" .$row[1]."</td>"; 
    echo "<td>".$row[2]."</td>"; 
    echo "<td>".$row[3]."</td>";
    echo "</tr>"; } 
echo "</table>"; 
?>

检查您的查询,您已经选择了订单。order_id不存在于所选表中,并添加一个条件将加入表order

SELECT products.product_title,orders.order_id,products.product_price, cart.qty 
FROM products, cart 
WHERE products.product_id=cart.p_id

是的,你在做正确的方式,但使用mysqli代替mysql,它从php7中删除,并从php弃用。这里是查询,(我从Eyy的回答中得到帮助)

SELECT tbl_a.column1 , tbl_a.column2 
   tbl_b.column1 , tbl_b.column2, 
   tbl_c.column1,  tbl_c.column2
FROM  tbl_a INNER JOIN tbl_b ON 
tbl_a.commonfield=tbl_b.commonfield
INNER JOIN tbl_c ON
tbl_a.commonfield=tbl_c.commonfield