遍历日期以查找特定日期 php SQL

Question

PHP MYSQL - 如何仅计算每天的价格总和？如何判断新的一天何时从 0 重新开始计数。有没有办法说，现在是第 26 天，让我们从 0 重新开始计数，以便单独保存信息。在我的 SQL 表中，我有两列 Price 和 Lastvisit，25 日的最终结果应该是 289，而 26 日的总结果应该是 44+90+10 所以 144。如果可以，请提供帮助。谢谢。

• 价格
• 20
• 50
• 65
• 55
• 50
• 15
• 34
• 44
• 90

• 10

• 上次访问

• 2014-09-25
• 2014-09-25
• 2014-09-25
• 2014-09-25
• 2014-09-25
• 2014-09-25
• 2014-09-25
• 2014-09-26
• 2014-09-26

• 2014-09-26

  <?php
  $date_start = date("Y/m/d"); //Todays Date
  $end_date = date ("Y/m/d", strtotime("last month", strtotime($date_start))); //30 days         prior
  
  while (strtotime($date_start) >= strtotime($end_date)) { //run through each of the 30 days
  $date_start = date ("Y/m/d", strtotime("-1 day", strtotime($date_start))); //remove 1 day at a time.
  //echo $date_start . "<br>";
  $lastthirtydays .= substr($date_start,8)."|"; //explode each day to plug it in later
  $linegraphq = "SELECT History.Price,History.Lastvisit FROM History WHERE Lastvisit='$date_start'"; //sql 
  $linegraphqresult = mysql_query($linegraphq); ////query
  while($row = mysql_fetch_array($linegraphqresult)){ //get all results from query
  $dayofprice .= substr($row['Lastvisit'],8); //explode each DAY # only.
  //echo "COST: " . $row['Price'] . "DATE" . $row['Lastvisit'] . "<br>"; //this is just    the info im working with.
  $finalcost += $row['Price']; //this is summing all of the 30 days pricing
  $pricetoday .= $row['Price'] . "|" . $row['Lastvisit']. "|"; //now you can tell im getting lost...
  
  }
  }
  echo $dayofprice; //TEST
  echo $pricetoday; //TEST
  $explodedmonth = explode('|',$lastthirtydays);
  $explodedprice = explode('|',$pricetoday);
  //echo $explodedprice[1];
  //echo $finalcost;
  ?>
  

Answer 1

是我遗漏了什么还是你只想要总和？

SELECT SUM(Price) AS Total
FROM History
GROUP BY Lastvisit;