如何在上传到数据库之前删除金额上的货币符号？

Before it get's inserted to sql database the currency sign on amount is already removed.

You can use substr(). If the sign is in front of the amount, you just have to set the start value to 1. If the sign is behind the amount, you set the start value to 0 and the length value to the length of the amount.

For example: Sign in front of amount: substr("¥100",1); Sign after amount: substr("100€",0,3);

you can get your string replaced by using str_replace()

$string = str_replace( $search_for_sign, $replace_the_sign_with_nothing, $in_your_string );

For Example:

$string_with_target_sign = "$ value";
$formatted_string = str_replace("$" , "" , $string_with_target_sign);