: char(126) is the tilde character ( ~ ). The payload attaches this to the start of the data so that the resulting error message clearly displays the extracted value.
: Attempts to balance the trailing single quote of the original query to prevent a syntax error that might stop the script from running. Context of Use : char(126) is the tilde character ( ~ )
: Appends a logical condition. The /**/ is a comment used to bypass simple security filters that block spaces. extractvalue(1, concat(char(126), md5(1002059835))) : : char(126) is the tilde character ( ~ )