Ò׽ؽØÍ¼Èí¼þ¡¢µ¥Îļþ¡¢Ãâ°²×°¡¢´¿ÂÌÉ«¡¢½ö160KB

SQLÓï¾ä²éѯÊý¾Ý¿âÖÐÖØ¸´¼Ç¼µÄ¸öÊý

Ò»¸ösqlÓï¾ä£ºÒ»¸ö±ítestÓÐËĸö×Ö¶Îid,a,b,c,Èç¹û±íÖеļǼÓÐÈý¸ö×Ö¶Îa,b,c¶¼ÏàµÈ£¬Ôò˵Ã÷ÕâÌõ¼Ç¼ÊÇÏàͬµÄ£¬ÇóÏàͬµÄ¼Ç¼µÄ¸öÊý ¡£
select a,b,c,count(*) from (select c.a,c.b,c.c from test c) having count(*) >= 2 group by a,b,c
»òÕß
select zdbh,tdzl,zdmj,count(*) from ecaadmin.zdsx group by zdbh,tdzl,zdmj having count(*) >= 2


Ïà¹ØÎĵµ£º

sql serverµÄtinyintÀàÐÍÓë.netÖеÄË­¶ÔÓ¦

 .NETÖÐC#µÄbyte¹Ø¼ü×ÖÓ³Éä.NETµÄByte½á¹¹£º±íʾһ¸ö 8 λÎÞ·ûºÅÕûÊý¡£Byte ÖµÀàÐͱíʾֵ½éÓÚ 0 ºÍ 255 Ö®¼äµÄÎÞ·ûºÅÕûÊý¡£
.NETÖÐC#µÄshort¹Ø¼ü×ÖÓ³Éä.NETÖеÄInt16£ºÓзûºÅ 16 λÕûÊý£¬-32,768 µ½ 32,767¡£
SQL SERVERÖеÄtinyint:´Ó 0 µ½ 255 µÄÕûÐÍÊý¾Ý¡£´æ´¢´óСΪ 1 ×Ö½Ú¡£
sbyte£º´æ´¢8λ´ø·ûºÅÕûÊý¡£sbyt ......

SQLÊÖ¹¤×¢ÉäÔ­Àí

     ¹ØÓÚSQL×¢Èë(SQL Injection)µÄ·½·¨Æäʵ¶¼ºÜÆÕ±éºÍʹÓ㬹éÄÉÆðÀ´Ò²ºÜ·½±ã¡£Ò»°ã“ºÚ¿Í”ʹÓõÄÊÇÏֳɵŤ¾ßÈç“WEBÅÔ×¢¡¢°¢DÍøÂ繤¾ß°ü¡¢½ÌÖ÷XXX”µÈÕâЩ¶¼ÊǼ¯³ÉÁË
һЩ³£ÓõÄsql×¢ÈëÓï¾ä¡£ÏÂÃæÎÒ½«½éÉÜÈçºÎʹÓÃÊÖ¹¤×¢ÈëMYSQL,MSSQLÊý¾Ý¿â.
    Ò»°ã©¶´²ú ......

DBA³£ÓÃsql(Ò»)

--¼à¿ØË÷ÒýÊÇ·ñʹÓà alter index &index_name monitoring usage; alter index &index_name nomonitoring usage; select * from v$object_usage where index_name = &index_name;
--ÇóÊý¾ÝÎļþµÄI/O·Ö²¼ select df.name,phyrds,phywrts,phyblkrd,phyblkwrt,singleblkrds,readtim,writetim from v$filestat fs,v ......

SQLÖеÄDDL,DML,DCLÓïÑÔ

     ¸Ð¾õ×Ô¼ºÊDZȽϱ¿µÄ£¬Ñ§Ï°¹ýSQLÓïÑÔ£¬µ«ÊÇÈ´·Ö²»Ì«Çå³þDDL¡¢DML¡¢DCLÓïÑÔ£¬ËùÒÔÄØ£¬½ñÌì¾Íºñ×ÅÁ³Æ¤ÎÊÁËÀÏʦ£¬ÏÖÔÚ¾Í×Ô¼ºÄ¿Ç°µÄÁ˽âÀ´×ܽáһϡ£
1¡¢DDL£¨DATA DEFINITION LANGUAGE£©Êý¾ÝÃèÊöÓïÑÔ
     DDLÓï¾ä²»»á²úÉú»¹Ô­Êý¾Ý£¬ËùÒÔɾ³ýµÄÊý¾ÝÒ²ÊÇÎÞ·¨»Ö¸´µÄ
CREATE - to ......

sql server 2008 ·ÖÇø±íÎÊÌâ

    ¹«Ë¾Óиö±¨±íϵͳÏìÓ¦ËٶȲ»ÊǺÜÀíÏ룬µ÷Óŵ÷Á˺ü¸´Î£¬ÓеãЧ¹û£¬µ«²»ÊǺÜÈÃÈËÂúÒâ¡£×î½üÓÖ¿ªÊ¼µ÷ÓÅ£¬ÊÔÁËÊÔsql server 2008µÄ·ÖÇø±í¹¦ÄÜ£¬¿´¿´ÊDz»ÊÇ·ÖÇøÖ®ºóËÙ¶È¿ÉÒÔ¿ìÒ»µã¡£
    ÓÃÁËÒ»¸ö°ÙÍò¼¶Êý¾ÝµÄ»ã×ܱíÀ´×ö·ÖÇø£¬·ÖÇøµÄÏë·¨Êǰ´ÔÂÀ´·ÖÇø£¬Ò»¸ö·ÖÇø´æ´¢Ò»¸öÔµÄÊý¾Ý£¬Ò»¸ö·ÖÇøµ ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ