The Background I was trying to solve the fourth realistic mission in hackthissite.org, and couldn't figure out exactly what SQL I should inject into the URL to retrieve the list of emails.
Union select null, null, null, null, null, null, null from information_schema.tables. for a small database containing three tables. this instruction is used in sql injection I tried it and it worked but I didn't really know how it works can somebody help me...
Note: A NULL value is different from a zero value or a field that contains spaces. A field with a NULL value is one that has been left blank during record creation!
413 подписчиков, 1,617 подписок, 4,157 публикаций — посмотрите в Instagram фото и видео null (@null_null).
Not Null check can be implemented using ISNULL function.
MySQL allows columns to take "null" (not specified) values by default, so we'd better take a look ...
Null values can be used as a condition in the WHERE and HAVING clauses. For example, a WHERE clause can specify a column that, for some rows
The null character (also null terminator or null byte) is a control character with the value zero. It is present in many character sets, including ISO/IEC 646 (or ASCII), the C0 control code, the Universal Coded Character Set (or Unicode), and EBCDIC.
NULL is special in SQL. NULL indicates that the data is unknown, inapplicable or even does not exist. In other words, NULL represents that the data is missing in the database. For example, if an employee does not have any phone number, you can store it as an empty string.