SQL ÃæÊÔÌâÒ»
1.ÓÃÒ»ÌõSqlÓï¾ä²éѯ³öÿÃŹ¦¿Î¶¼´óÓÚ80·ÖµÄѧÉúÐÕÃû
Name
Class
Result
ÕÅÈý
ÓïÎÄ
56
ÕÅÈý
Êýѧ
88
ÀîËÄ
ÓïÎÄ
92
ÀîËÄ
Êýѧ
100
ÍõÎå
ÓïÎÄ
88
ÍõÎå
Êýѧ
99
ÍõÎå
Ó¢Óï
99
-------------------------------------------------------------------------------
´ð°¸£º
SELECT DISTINCT name
from exercise
WHERE name NOT IN (SELECT name from exercise WHERE result < 80))
2. ɸѡ³ö±í"A"ÖеÚ31µ½40¼Ç¼£¨±íÖÐIDΪÖ÷¼ü,×¢Ò⣺IDºÅÓпÉÄܲ»ÊÇÁ¬ÐøµÄ£©
------------------------------
´ð°¸£º
SELECT TOP 10 from (SELECT TOP 40 * from A ORDER BY id DESC)
Ïà¹ØÎĵµ£º
±íÖÐÖ÷¼ü±ØÐëΪ±êʶÁУ¬[ID] int IDENTITY (1,1)
1.·ÖÒ³·½°¸Ò»£º(ÀûÓÃNot InºÍSELECT TOP·ÖÒ³)
Óï¾äÐÎʽ£º
SELECT TOP Ò³¼Ç¼ÊýÁ¿ *
from ±íÃû
WHERE (ID NOT IN
(SELECT TOP (ÿҳÐÐÊý*(Ò³Êý-1)) ID
from ±íÃû
ORDER BY ID))
ORDER BY ID
//×Ô¼º»¹¿ÉÒÔ¼ÓÉÏһЩ²é ......
ÔÚsql Server ´Ó¿ª·¢»·¾³ÍùÉú²ú»·¾³²¿Êðʱ£¬ÒòΪ¿Í»§ÄÇÀïÓõÄÊÇÓ¢ÎÄ°æ±¾£¬ËùÒÔ´´½¨Êý¾Ý¿âÒÔºó£¬ÒªÉèÖÃÒ»ÏÂÊý¾Ý¿âÅÅÐò¹æÔò¡£
µ«ÊÇÔÚ´æ´¢¹ý³ÌÖУ¬ÓеijÌÐòԱʹÓÃÁËÁÙʱ±í£¬ÒòΪÁÙʱ±íÊÇ´æ´¢ÔÚϵͳÊý¾Ý¿âtempdbÖУ¬Èç¹ûϵͳÁÙʱÊý¾Ý¿âûÓнøÐÐÅÅÐò¹æÔòµÄÉèÖ㬳ÌÐò»¹Êdzö´í£¬½â¾ö°ì·¨¾ÍÊÇÉèÖÃÁÙʱÊý¾Ý¿âµÄÅÅÐò¹æÔò»òÕß´´½¨ÁÙÊ ......
×Ö·ûÀàÐÍ£º
CHAR(size)£º¹Ì¶¨³¤¶È×Ö·û´®£¬×î´ó³¤¶È2000 bytes
VARCHAR2(size)£º¿É±ä³¤¶ÈµÄ×Ö·û´®£¬×î´ó³¤¶È4000 bytes£¬¿É×öË÷ÒýµÄ×î´ó³¤¶È749
NCHAR(size)£º¸ù¾Ý×Ö·û¼¯¶ø¶¨µÄ¹Ì¶¨³¤¶È×Ö·û´®£¬×î´ó³¤¶È2000 bytes
NVARCHAR2(size)£º¸ù¾Ý×Ö·û¼¯¶ø¶¨µÄ¿É±ä³¤¶È×Ö·û´®£¬×î´ó³¤¶È4000 byte
LONG£º±ä³¤µÄ×Ö·û´®£¬×î´ó³¤¶ÈÏÞ ......
ÒªÇó£º °´ lct1£¬ lct2 ÅÅÐòºóµÄÇ°Á½Ìõ¼Í¼£¬ÏÔʾΪÏÂÁнá¹û£º
item_cd1 item_cd2 lct
01 a   ......