更新大型数据集

Question

我可以上传一个包含 3000 条记录的 csv 文件，但是当我尝试更新时，需要很长时间，导致请求超时错误。

插入：

$sqlInsert = "INSERT ignore into datanyc (`Symbol`,`Data_date`,`Open`,`High`,`Low`,`Last`,`Volume`)
                values ('".$column0."','".$dataDate."','".$column[2]."','".$column[3]."',
                '".$column[4]."','".$column[5]."','".$column[6]."')";

更新语句：

$date_query="SELECT max(Data_date) as Prev_date FROM datanyc WHERE Data_date < '$dataDate' ";
$date_result=mysqli_query($con,$date_query);
$fetch=mysqli_fetch_array($date_result);
$Prevdate=$fetch['Prev_date'];
$temp="SELECT Last as last, Symbol as symbol FROM datanyc WHERE Data_date = '$Prevdate'";
$date1=mysqli_query($con,$temp);
while($row=mysqli_fetch_array($date1))
{
    //array_push($symbol,$row['symbol']);
    //array_push($last,$row['last']);
    $qry="UPDATE datanyc SET Prevclose = '".$row['last']."' WHERE Symbol LIKE '".$row['symbol']."' AND Data_date= $dateDate";
    mysqli_query($con,$qry);
    //$date=$row['max(Data_date)'];
}

Answer 1

首先，在 Symbol 和 Data_date 列上添加索引，

其次，将您的更新查询更改为一个查询，这样您就不需要像这样循环更新：

$sql = "UPDATE
          datanyc AS a
        INNER JOIN datanyc b ON a.symbol = b.symbol
                     AND b.Data_date = '$Prevdate'
        SET a.Prevclose = b.last";
$date1 = mysqli_query($con, $sql);

更新大型数据集

Update large dataset

php

mysql

sql-update

bulkupdate