Question

好的，所以我在Mysql服务器上有一个卖家评论的表：

SellerReview (ID, User_ID, Time, Review, Seller_id)

和另一个表Seller_id与名称Users（ID，name）相关联的表。

现在我必须进行查询，以便选择元组（V1，V2），其中V2的最大评论严格小于V1的最小评论。

我拥有的是：

SELECT U1.name AS V1, U2.naam AS V2
FROM Users AS U1, Users AS U2, SellerReview AS S1, SellerReview AS S2
WHERE U1.id = S1.seller_id   
  AND G2.id = V2.seller_id 
  AND ((SELECT MAX(S.Review) 
        FROM SellerReview AS S 
        WHERE S.Seller_id = U1.id) > (SELECT MIN(S.review) 
                                      FROM SellerReview AS S 
                                      WHERE S.Seller_id = G2.id))

但我找不到合适的桌子。有谁知道这个问题或任何可以帮助我的人？谢谢！

Answer 1

要让所有评论者都不重复，请加入having。从那里，您可以使用SELECT U1.name AS V1, U2.name AS V2 FROM Users AS U1 JOIN SellerReview AS S1 on U1.id = S1.seller_id JOIN Users AS U2 ON U2.id < U1.id JOIN SellerReview S2 on U2.id = S2.seller_id GROUP BY U1.name, U2.name HAVING MAX(S2.review) < MIN(S1.review)确保第一个用户的最大审核小于另一个用户的最小审核。

Users.name

此查询假定Users.id是唯一的。如果不是，则应该按// $source = file_get_contents($file); $source = 'Array ( [f_name] => YOKICHI [l_name] => KOSHIZAWA [name] => YOKICHI KOSHIZAWA [street_address] => 7164 fake [city] => CANTON [state] => MI [zip] => 48187 [country] => United States [phone] => 734-354-6599 [email] => ykoshizawxxa@att.net [discount_percent] => 0.00 [discount_amount] => 0 [discount_items] => [shipping_region] => USA [shipping_type] => [shipping_priority] => [shipping_options] => [shipping_total] => 0 )'; // convert input to array $arr = explode(PHP_EOL, $source); // clean top and bottom of the array array_shift($arr); array_shift($arr); array_pop($arr); // init final array $final = array(); foreach($arr as $v) { $o = array(); $v = preg_match_all('#\[([a-zA-Z0-9 _.-]+)\] => (.*)#', $v, $o); $key = $o[1][0]; $val = (isset($o[2][0])) ? $o[2][0] : ''; // fill final $final[$key] = $val; } // init the filtered array $sort = array(); // keys you want to have in $keys = array('f_name','l_name','street_address','city','state','zip','phone','country'); foreach($final as $k => $v) { if(in_array($k, $keys)) { $sort[$k] = $v; } } var_dump($sort);进行分组，然后加入“用户”表以获取名称。

搜索最大值并与SQL

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