我有3个表格。
1st -> products 2nd -> labels 3rd -> connectionTable
我想选择所有贴标签的产品。 我有两种方法。 我要问的是,什么是更重要的。
1st way-> 两个查询在使用时使用
$query = "SELECT * FROM products"; (美元)
while($row = mysql_fetch_array($result, MYSQL_ASSOC))
{
$query = "SELECT *
FROM connectionTable
INNER JOIN labels ON labels.labelID = connectionTable.labelID
WHERE productID = " . $row[ labelID ];
..
..
}
编号
2nd way-> using group_CONCAT(CONCAT)
例如:
SELECT GROUP_CONCAT(labelName)
FROM connectionTable
INNER JOIN labels ON labels.labelID = connectionTable.labelID
INNER JOIN products ON products.productID = connectionTable.productID
WHERE productID = " . $row[ labelID ] . " GROUP BY productID;
(美元)