不正確的MySQL查詢更新

Question

我想篩選數據庫記錄，如果有重複的記錄我會將記錄標記爲deleted = 1。不幸的是，我無法正確更新我的記錄，我嘗試使用limit 1更新記錄，但我只更新了1條記錄，如果我沒有使用limit 1它將更新整個記錄。

以上是我的數據庫表，我需要做的是，假設有一堆不同point_id記錄和過濾我只1。現在我想查詢按日期排序的記錄ASC，並將所有記錄更新爲期望最後記錄的deleted = 1。

這是我的源代碼。我現在面臨的問題是它會更新所有記錄，如果我使用LIMIT 1它只會更新1條記錄。

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

你可以有一個子查詢，它獲取要更新的記錄並將其與表本身連接起來，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 

如果去掉子查詢裏面的WHERE條款，都爲每一位客戶的第一個記錄將被更新。

Answer 2

你需要這個：

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

另一種風格：

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