Question

我有一个sql表，其中包含我需要在另一个表中加入的字符串。首先，我从SQL表中获取了字符串：

$sql = "Select coupons.restrict_to_products From coupons Where coupons.coupon_id = 2";
$result = mysql_query($sql);
$row = mysql_fetch_row($result);
$array2=implode(",", $row);

所以，如果我现在回复$array2，它就会向我显示＆＃34; 42,43,73＆＃34;这就是我需要的。现在我想尝试加入另一个表格，结果如下：

$query = mysql_query("SELECT products_name FROM products_description WHERE products_id IN ($array2)");
while ($row2 = mysql_fetch_assoc($query)) {
    $array3=implode(",", $row2);
    echo $array3."<br>";
}

代码有效，但由于某种原因，它会向我显示每个产品名称3次，而不仅仅是一次。 echo的结果是：

Productname 1
Productname 1
Productname 1
Productname 2
Productname 2
Productname 2
Productname 3
Productname 3
Productname 3

我错过了什么？

Answer 1

使用group by

group by Productname

或者您可以尝试distinct

Answer 2

优惠券可能已应用于相同的产品，因此它会返回相同产品的3次。尝试group id产品SELECT products_name FROM products_description WHERE products_id IN ($array2) GROUP BY products_id，这将是唯一的。试试 -

outer apply

Answer 3

使用此

$query = mysql_query("SELECT DISTINCT(products_name) FROM products_description WHERE products_id IN ($array2) ");
while ($row2 = mysql_fetch_assoc($query)) {
    $array3=implode(",", $row2);
    echo $array3."<br>";
}

OR

$query = mysql_query("SELECT products_name FROM products_description WHERE products_id IN ($array2) group by products_id ");

Answer 4

或者如果行不重复，您可以获取与这些ID相关联的所有名称

SELECT products_id,GROUP_CONCAT(products_name) AS products_names
FROM products_description
WHERE products_id IN ($array)
GROUP BY products_id

sql查询显示每个结果3次，而不仅仅是一次

4 个答案: