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

ÂÛ̳Àï¿´µ½µÄÒ»¸öSQLÎÊÌâ¼°½â´ð

ÎÊÌ⣺
ÓÐÒ»¸ö·ÖÊý±í
id classid,score
1  01    120
2  01    128
3  02    98
4  04    134
5  04    78
ÏÖÔÚҪͳ¼Æ ¸÷°àscore >120,ºÍ´óÓÚ90·ÖµÄÈËÊý
´ïµ½ÈçÏÂЧ¹û
classid >120 >90
01    10    29
02    9      32
03    0      20
´ð°¸£º
select
classid,
sum
(
case
when
score
>
120
then
1
else
0
end
)
as
[
>120
]
,
sum
(
case
when
score
>
90 and score <=120
then
1
else
0
end
)
as
[
>90
]
from
tb
group
by
classid


Ïà¹ØÎĵµ£º

MyEclipseÁ¬½ÓSQL Server 2000´íÎóÅųý

ÔÚÁ¬½ÓSQL Server 2000Êý¾Ý¿âʱ£¬ÏµÍ³ÌáʾÈçÏ´íÎó£º
ÔÚÍøÉÏѰÕÒµ½´¦Àí·½·¨£º
(°ÑSQL server updateµ½sp4)
1¡¢ÔÚ²éѯ·ÖÎöÆ÷ÖÐÊäÈë select @@version ²¢Ö´ÐÐ
SQL Server 2000 °æ±¾ºÍ¼¶±ð
@@VERSION
²úÆ·¼¶±ð
 
SQL Server 2000 ԭʼ°æ±¾
8.00.194
RTM
 
Database Components SP1
8.00.384
SP1 ......

SQL SERVER 2005 Ò³ÃæÎļþÍ·²¿½á¹¹

       Next up in the Inside the Storage Engine series is a discussion of page structure. Pages exist to store records. A database page is an 8192-byte (8KB) chunk of a database data file. They are aligned on 8KB boundaries within the data files, starting at byte-offset ......

SQL SERVER ²Î¿¼£ºÓαê(Cursor)µÄ½²½âÓëʵÀý

 
ÔÚÊý¾Ý¿âÖУ¬ÓαêÊÇÒ»¸öÊ®·ÖÖØÒªµÄ¸ÅÄî¡£ÓαêÌṩÁËÒ»ÖÖ¶Ô´Ó±íÖмìË÷³öµÄÊý¾Ý½øÐвÙ×÷µÄÁé»îÊֶΣ¬¾Í±¾ÖʶøÑÔ£¬Óαêʵ¼ÊÉÏÊÇÒ»ÖÖÄÜ´Ó°üÀ¨¶àÌõÊý¾Ý¼Ç¼µÄ½á¹û¼¯ÖÐÿ´ÎÌáȡһÌõ¼Ç¼µÄ»úÖÆ¡£Óαê×ÜÊÇÓëÒ»ÌõT_SQL Ñ¡ÔñÓï¾äÏà¹ØÁª£¬ÒòΪÓαêÓɽá¹û¼¯£¨¿ÉÒÔÊÇÁãÌõ¡¢Ò»Ìõ»òÓÉÏà¹ØµÄÑ¡ÔñÓï¾ä¼ìË÷³öµÄ¶àÌõ¼Ç¼£©ºÍ½á¹û¼¯ÖÐÖ¸ ......

ÔÚSQLÖÐʹÓÃnow()µ¼ÖµÄÐÔÄÜϽµ(MySQL)

×öÊý¾Ý¿âµ÷ÓÅ£¬Ò»¸ö¼òµ¥µÄtip¾ÍʹÐÔÄÜÌáÉýÒ»´ó¿éʱ£¬±»°ïÖúµÄÈË×ÔÈ»ÊǸßÐ˶øÇҸм¤£¬ÎÒÒ²ÊÇÂúÐÄ»¶Ï²¡£ÓÃËùѧ°ïÖúÁËËûÈË£¬Ò²ËµÃ÷»¹ÊÇÓÐÒ»¼¼Ö®³¤µÄ£¬ÓÐÒ»ÃÅÄܹ»Ñø»î×Ô¼ºµÄÊÖÒÕ¡£Ò²ËãÊÇÊÖÒÕÈ˰¡¡£
ͬÊÂÈÃÎÒ°ïÖúÓÅ»¯£¬ÔÚslow query logÀï·¢ÏÖÓÐÁ½¸öSQLÖ´ÐеĴÎÊý×î¶à£¬²¢ÇÒÿ´Î¶¼ÔÚÁ½ÃëÒÔÉÏ¡£ÓÃexplain¿´ÁË£¬Ò²Î´·¢ÏÖË÷ÒýʹÓ÷ ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ