如何将所有amounts
相加,以便而不是返回所有单个提款金额的选择脚本返回其中一个数字加在一起?
<?php
$end_date = strtotime($nextdate);
$start_date = strtotime($statement_date);
$username = $usr['username'];
$result = mysql_query("SELECT * FROM `usr_withdraw` WHERE `timestamp` > '$start_date' AND `timestamp` < '$end_date' AND `username` = '$username'")or die(mysql_error());
while($balance = mysql_fetch_array( $result )) {
echo $balance['amount'];
}
?>
要仅返回 1 行,其中包含所有金额的总和,请使用 sql sum()
函数。
SELECT sum(amount) FROM `usr_withdraw` WHERE ...
do
$result = mysql_query("SELECT SUM(amount) FROM `usr_withdraw` WHERE `timestamp` > '$start_date' AND `timestamp` < '$end_date' AND `username` = '$username'")or die(mysql_error());
但也要记住,这些 mysql_* 函数从版本 7 开始就不在 PHP 中了,那么你的代码很快就会过时。理想的情况是使用 mysqli_* 函数或 PDO。