$ _ GET ['goods _ id'] + 0 usage details

This article is about $ _ GET [ Purpose:To prevent SQL injection, tid and goods_id are all positive integers? Tid = 1 or 1.
Principle:No matter how sinister your parameter is, after + 0, it turns into a numeric type.

For example '? Tid = 1 or 1', $ _ GET ['tid'] + 0, and the value is 1;

Some students asked why you don't need to convert (int) strongly or intval.
1: Which method is used for the same purpose?
2: + 0. it only needs to be 2 characters, 5 for (int), and 8 for intval.
3: For + 0, I don't need to worry about whether $ tid is an integer, float type, or a long integer larger than 2 ^ 32 (such as getting bigint in mysql). + 0 can be used.
However, a strong conversion will cause overflow. of course, you can say that I use float for conversion. isn't it a different score.