SQL·ÖÒ³²éѯ
thunder:
1.MYSQLʵÏÖ
mysql> select * from user;
+----+----------+----------+-----------------+
| ID | username | password | email |
+----+----------+----------+-----------------+
| 1 | admin | admin | abc@yahoo.cn |
| 2 | thomas | 159753 | thomas@yahoo.cn |
| 3 | thomas1 | 159753 | thomas@yahoo.cn |
| 4 | huhu | 159753 | hu@yahoo.cn |
| 5 | fdg | dfg | fdg |
| 6 | sdf | sd | sdf@yahoo.cn |
| 7 | d | d | d@d.cn |
+----+----------+----------+-----------------+
7 rows in set (0.00 sec)
mysql> select * from user limit 3,2;
+----+----------+----------+-------------+
| ID | username | password | email |
+----+----------+----------+-------------+
| 4 | huhu | 159753 | hu@yahoo.cn |
| 5 | fdg | dfg | fdg |
+----+----------+----------+-------------+
2 rows in set (0.00 sec)
mysql>
===================================================
2.MSSQLServerʵÏÖ
select top 5 function_id,function_name from d_function
where function_id not in (select top 5 function_id from d_function)
6 ÔÂͳ¼Æ
7 ²¿ÃŲéѯ
8 ¹«Ë¾²éѯ
9 ¹¤³ÌÕбê
10 ¹¤³Ì×ܽá
Ïà¹ØÎĵµ£º
http://www.umgr.com/blog/PostView.aspx?bpId=36294
1. Ö´ÐÐsqlÓï¾ä
int sqlite3_exec(sqlite3*£¬ const char *sql£¬ sqlite3_callbacksql Óï·¨
£¬ void *£¬ char **errmsg );
Õâ¾ÍÊÇÖ´ÐÐÒ»Ìõ sql Óï¾äµÄº¯Êý¡£
µÚ1¸ö²ÎÊý²»ÔÙ˵ÁË£¬ÊÇÇ°Ãæopenº¯ÊýµÃµ½µÄÖ¸Õ롣˵ÁËÊǹؼüÊý¾Ý½á¹¹¡£
µÚ2¸ö²ÎÊýconst char ......
1.Ñ¡Ôñ×îÓÐЧÂʵıíÃû˳Ðò(Ö»ÔÚ»ùÓÚ¹æÔòµÄÓÅ»¯Æ÷ÖÐÓÐЧ)¡¡¡¡
¡¡¡¡ SQLSERVERµÄ½âÎöÆ÷°´ÕÕ´ÓÓÒµ½×óµÄ˳Ðò´¦Àífrom×Ó¾äÖеıíÃû£¬Òò´Ëfrom×Ó¾äÖÐдÔÚ×îºóµÄ±í£¨»ù´¡±ídriving table£©½«±»×îÏÈ´¦Àí£¬ÔÚfrom×Ó¾äÖаüº¬¶à¸ö±íµÄÇé¿öÏ£¬±ØÐëÑ¡Ôñ¼Ç¼ÌõÊý×îÉٵıí×÷Ϊ»ù´¡±í£¬µ±SQLSERVER´¦Àí¶à¸ö±íʱ£¬»áÔËÓÃÅÅÐò¼°ºÏ²¢µÄ·½Ê½Á ......
ÔÚѧϰSQLʱ¿´µ½µÄһƬºÜºÃµÄÎÄÕ£¬ÌØÌù³öÀ´ºÍ´ó¼ÒÒ»Æð·ÖÏí£¡
ÎÒÃÇÒª×öµ½²»µ«»áдSQL,»¹Òª×öµ½Ð´³öÐÔÄÜÓÅÁ¼µÄSQLÓï¾ä¡£
£¨1£©Ñ¡Ôñ×îÓÐЧÂʵıíÃû˳Ðò(Ö»ÔÚ»ùÓÚ¹æÔòµÄÓÅ»¯Æ÷ÖÐÓÐЧ)£º
OracleµÄ½âÎöÆ÷°´ÕÕ´ÓÓÒµ½×óµÄ˳Ðò´¦Àífrom×Ó¾äÖеıíÃû£¬from×Ó¾äÖÐдÔÚ×îºóµÄ±í(»ù´¡±í driving table)½«±»×îÏÈ´¦ ......
£¨18£©ÓÃEXISTSÌæ»»DISTINCT£º
µ±Ìá½»Ò»¸ö°üº¬Ò»¶Ô¶à±íÐÅÏ¢(±ÈÈ粿ÃűíºÍ¹ÍÔ±±í)µÄ²éѯʱ,±ÜÃâÔÚSELECT×Ó¾äÖÐʹÓÃDISTINCT¡£Ò»°ã¿ÉÒÔ¿¼ÂÇÓÃEXISTÌæ»», EXISTS ʹ²éѯ¸üΪѸËÙ,ÒòΪRDBMSºËÐÄÄ£¿é½«ÔÚ×Ó²éѯµÄÌõ¼þÒ»µ©Âú×ãºó,Á¢¿Ì·µ»Ø½á¹û¡£Àý×Ó£º
(µÍЧ):
SELECT DISTINCT DEPT_NO,DEPT_NAME  ......
µÍЧ: (Ë÷ÒýʧЧ)
SELECT … from DEPARTMENT WHERE DEPT_CODE IS NOT NULL;
¸ßЧ: (Ë÷ÒýÓÐЧ)
SELECT … from DEPARTMENT WHERE DEPT_CODE >=0;
£¨27£©×ÜÊÇʹÓÃË÷ÒýµÄµÚÒ»¸öÁУº
Èç¹ûË÷ÒýÊǽ¨Á¢ÔÚ¶à ......