MySQL查询更新不正确

Question

我想过滤数据库记录，如果有重复记录，我会将记录标记为deleted = 1。很遗憾，我无法正确更新我的记录，我确实尝试使用limit 1来更新记录，但我只更新了1条记录，如果我没有使用limit 1它将更新整个记录。

以上是我的数据库表，我需要做的是，假设有一堆不同point_id的记录，我只过滤到1。现在我想查询按日期ASC排序的记录，并将所有记录更新为deleted = 1期望最后一条记录。

这是我的源代码。我现在面临的问题是它将更新所有记录，如果我使用LIMIT 1它只会更新1条记录。

while($total > 1){
    $total--;
    $sql = sprintf("SELECT * 
        FROM customers_profiles_game_logs 
        WHERE point_id='$points_filter_row[point_id]' 
        AND customer_id='$sql_customer_row[customer_id]'
        ORDER BY date_created ASC");
    $query = mysql_query($sql) or die(mysql_error());
    $row = mysql_fetch_array($query);
    $num_rows = mysql_num_rows($query);

    for ($i = 1; $i < $num_rows; $num_rows--) {
       echo $sqli = sprintf("UPDATE customers_profiles_game_logs 
           SET deleted='1' 
           WHERE customer_id='$sql_customer_row[customer_id]'
           AND point_id='$row[point_id]' LIMIT 1"); 
             mysql_query($sqli) or die(mysql_error());
    }
}

Answer 1

你可以有一个子查询来获取要更新的记录并将其与表本身连接起来，例如。

UPDATE  customers_profiles_game_logs a
        INNER JOIN
        (
            SELECT  customer_id, MIN(date) date
            FROM    customers_profiles_game_logs
            WHERE   customer_id = 1                -- <== ID HERE
        ) b ON  a.customer_id = b.customer_id
                AND a.date = b.date
SET     a.deleted = 1

如果删除子查询中的WHERE子句，则每个客户的所有第一条记录都将更新。

Answer 2

你需要这个：

  UPDATE  customers_profiles_game_logs a
        INNER JOIN
        (
            SELECT  customer_id, MIN(date) date
            FROM    customers_profiles_game_logs
            WHERE   customer_id = 1                -- <== ID HERE
        ) b ON  a.customer_id = b.customer_id
            SET     a.deleted = 1

http://sqlfiddle.com/#!2/6c440/1

另一种风格：

UPDATE  customers_profiles_game_logs a
        INNER JOIN
        (
            SELECT  customer_id, MIN(date) date
            FROM    customers_profiles_game_logs
        ) b ON  a.customer_id = b.customer_id
            SET     a.deleted = 1

http://sqlfiddle.com/#!2/88e7c/1