Ò׽ؽØͼÈí¼þ¡¢µ¥Îļþ¡¢Ãâ°²×°¡¢´¿ÂÌÉ«¡¢½ö160KB

SQL²éѯÓÅ»¯,×¢ÒâwhereÌõ¼þµÄ˳Ðò

×÷Õß:ÂÞ´ú¾ù ldj_work#126.com   תÔØÇë±£³ÖÍêÕûÐÔ
1.²âÊÔ±í
    employee
    ¹ÍÔ±id     ²¿ÃÅid      н½ð
    emp_id    dept_id    salary
      01            01           1050
      02             01           2000
   ok,ÎÒÃÇÒª²éÕÒ²¿ÃÅ01ÏÂ,н½ð¸ßÓÚ1000µÄ¹ÍÔ±
2.Ô­Ôò¼°Á½¸öSQLµÄ¶Ô±È
Ô­Ôò,¶àÊýÊý¾Ý¿â¶¼ÊÇ´Ó ×óµ½ÓÒµÄ˳Ðò´¦ÀíÌõ¼þ,°ÑÄܹýÂ˸ü¶àÊý¾ÝµÄÌõ¼þ·ÅÔÚÇ°Ãæ,¹ýÂËÉÙµÄÌõ¼þ·ÅºóÃæ
SQL1: select * from employee
            where salary >1000     --Ìõ¼þ1,¹ýÂ˵ÄÊý¾Ý½ÏÉÙ
                 and   dept_id='01'    --Ìõ¼þ2,¹ýÂ˵ÄÊý¾Ý±ÈÌõ¼þ1¶à
ÉÏÃæµÄSQL¾Í²»·ûºÏÎÒÃǵÄÔ­ÔòÁË,Ó¦¸Ã°Ñ¹ýÂËÊý¾Ý¸ü¶àµÄÌõ¼þ·ÅÔÚÇ°Ãæ,Òò´Ë¸ÄΪÏÂÃæÕâÑù¸üºÃ
             select * from employee
              where   dept_id='01'     --¹ýÂ˸ü¶àÊý¾ÝµÄÌõ¼þ·ÅÔÚÇ°Ãæ
                  and   salary > 1000


Ïà¹ØÎĵµ£º

SQL UnionºÍSQL Union AllÓ÷¨

UNION Ö¸ÁîµÄÄ¿µÄÊǽ«Á½¸ö SQL Óï¾äµÄ½á¹ûºÏ²¢ÆðÀ´¡£´ÓÕâ¸ö½Ç¶ÈÀ´¿´£¬ UNION ¸ú JOIN ÓÐЩÐíÀàËÆ£¬ÒòΪÕâÁ½¸öÖ¸Á¿ÉÒÔÓɶà¸ö±í¸ñÖÐߢȡ×ÊÁÏ¡£ UNION µÄÒ»¸öÏÞÖÆÊÇÁ½¸ö SQL Óï¾äËù²úÉúµÄÀ¸Î»ÐèÒªÊÇͬÑùµÄ×ÊÁÏÖÖÀà¡£ÁíÍ⣬µ±ÎÒÃÇÓà UNIONÕâ¸öÖ¸Áîʱ£¬ÎÒÃÇÖ»»á¿´µ½²»Í¬µÄ×ÊÁÏÖµ (ÀàËÆ SELECT DISTINCT)¡£ unionÖ»Êǽ«Á½¸ö½á¹ ......

SQL JOIN

SQL JOIN
 
SQL join ÓÃÓÚ¸ù¾ÝÁ½¸ö»ò¶à¸ö±íÖеÄÁÐÖ®¼äµÄ¹Øϵ£¬´ÓÕâЩ±íÖвéѯÊý¾Ý¡£
Join ºÍ Key
ÓÐʱΪÁ˵õ½ÍêÕûµÄ½á¹û£¬ÎÒÃÇÐèÒª´ÓÁ½¸ö»ò¸ü¶àµÄ±íÖлñÈ¡½á¹û¡£ÎÒÃǾÍÐèÒªÖ´ÐÐ join¡£
Êý¾Ý¿âÖеıí¿Éͨ¹ý¼ü½«±Ë´ËÁªÏµÆðÀ´¡£Ö÷¼ü£¨Primary Key£©ÊÇÒ»¸öÁУ¬ÔÚÕâ¸öÁÐÖеÄÿһÐеÄÖµ¶¼ÊÇΨһµÄ¡£ÔÚ±íÖУ¬Ã¿¸öÖ÷¼üµÄ ......

SQL JOINÖ®ÍêÈ«Ó÷¨

×î½üÔÚ×ömysqlµÄÐÔÄÜÓÇ»¯£¬×öµ½¶à±íÁ¬½Ó²éѯ£¬±È½ÏÍ·ÌÛ£¬¿´ÁËһЩjoinµÄ×ÊÁÏ£¬ÖÕÓڸ㶨£¬ÕâÀï·ÖÏí³öÀ´£¡
ÍâÁª½Ó¡£ÍâÁª½Ó¿ÉÒÔÊÇ×óÏòÍâÁª½Ó¡¢ÓÒÏòÍâÁª½Ó»òÍêÕûÍⲿÁª½Ó¡£    
  ÔÚ   from   ×Ó¾äÖÐÖ¸¶¨ÍâÁª½Óʱ£¬¿ÉÒÔÓÉÏÂÁм¸×é¹Ø¼ü×ÖÖеÄÒ»×éÖ¸¶¨£º  
 &n ......

Visual Basic 6.0 Óë SQL Server µÄÁ½ÖÖÁ¬½Ó

VBͨ¹ýADOÁ¬½ÓSQL ServerÊý¾Ý¿â¿ÉÒÔ·ÖΪÓÐÔ´Êý¾Ý¿âÁ¬½ÓºÍÎÞÔ´Êý¾Ý¿âÁ¬½Ó£¬Çø±ðËüÃÇ¿´ÊÇ·ñʹÓÃÁËDSN£¨Êý¾ÝÔ´Ãû³Æ£©À´¾ö¶¨¡£
1   ÎÞÔ´Êý¾Ý¿âÁ¬½Ó
Æäʵ£¬“ÎÞÔ´Êý¾Ý¿â”Á¬½ÓÒ²²¢²»ÊÇ˵²»ÐèÒªÊý¾ÝÔ´£¬Èç¹ûûÓÐÊý¾ÝÔ´ÔòÁ¬½ÓÊÇÖ½ÉÏ̸±ø£¬Ö»ÊDz»ÐèÒªÅäÖÃODBCÊý¾ÝÔ´£¬ÀûÓÃADO¾Í¿Éͨ¹ý´úÂë½øÐÐÁ¬½Ó¡£
1.1 ADO ......

MS SQL Server²éѯÓÅ»¯·½·¨

²éѯËÙ¶ÈÂýµÄÔ­ÒòºÜ¶à£¬³£¼ûÈçϼ¸ÖÖ 
1¡¢Ã»ÓÐË÷Òý»òÕßûÓÐÓõ½Ë÷Òý(ÕâÊDzéѯÂý×î³£¼ûµÄÎÊÌ⣬ÊdzÌÐòÉè¼ÆµÄȱÏÝ)  
2¡¢I/OÍÌÍÂÁ¿Ð¡£¬ÐγÉÁËÆ¿¾±Ð§Ó¦¡£ 
3¡¢Ã»Óд´½¨¼ÆËãÁе¼Ö²éѯ²»ÓÅ»¯¡£  
4¡¢ÄÚ´æ²»×ã 
5¡¢ÍøÂçËÙ¶ÈÂý 
6¡¢²éѯ³öµÄÊý¾ÝÁ¿¹ý´ó£¨¿ÉÒÔ²ÉÓöà´Î²éѯ£¬ÆäË ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØͼ | ¸ÓICP±¸09004571ºÅ