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

mysql Ò»µÀСÌâ

 ±íÃûΪtableµÄ±íÄÚÈÝÈçÏÂ
Year month value
2009  1    1.1
2009  2    1.2
2009  3    1.3
2009  4    1.4
2010  1    2.1
2010  2    2.2
2010  3    2.3
2010  4    2.4
ÒªÇó²éѯ½á¹ûΪ
year  m1  m2  m3  m4
2009  1.1  1.2  1.3  1.4
2010  2.1  2.2  2.3  2.4
mysql> select year,sum(case when month=1 then value end) as 'm1',sum(case when m
onth=2 then value end) as 'm2',sum(case when month=3 then value end)as 'm3' from
 table2 group by year;


Ïà¹ØÎĵµ£º

LinuxÏ·ÖÎöMysqlÈÕÖ¾µÄºÃ¹¤¾ß–mysqlsla


´Óhttp://hackmysql.com/mysqlslaÏÂÔØmysqlsla£¬µ±Ç°×îаæÎª£º2.03
tar zxvf mysqlsla-2.03.tar.gz
cp mysqlsla-2.03/bin/mysqlsla /usr/local/bin
Èç¹ûÌáʾ“Can’t locate DBI.pm”£¬Ö´ÐÐÒÔÏÂÃüÁî
yum install perl-DBI perl-DBD-MySQL -y
Õâʱ¾Í¿ÉÒÔʹÓÃmysqlslaÁË£¬Ó÷¨ÈçÏÂ
mysqlsla -lt slo ......

php ͨ¹ýÍøÒ³µÄ·½Ê½±¸·ÝºÍ»¹Ô­mysqlÊý¾Ý¿â

 ×î½üÉÏÍøÕÒÁËһЩ¹ØÓÚ±¸·ÝmysqlÊý¾Ý¿âµÄ·½·¨£¬Ö÷Òª¾ÍÊÇͨ¹ýÍøÒ³µÄ·½·¨µ¼³öÊý¾Ý¿âµÄsql Îļþ£¬ÕÒµ½¸ö²»´íµÄ´úÂ룬µ«·¢ÏÖÖÐÎĵ¼³ö»áÂÒÂ룬ÓÚÊÇÉÔ΢ÐÞ¸ÄÁËһϣ¬ÏÂÃæÊDZ¸·ÝµÄ´úÂë
view plaincopy to clipboardprint?
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml ......

MySQLÊý¾Ý¿âµÄ¼òµ¥²Ù×÷

MySQLÊý¾Ý¿âµÄ¼òµ¥²Ù×÷
Ò».´´½¨Êý¾Ý¿â ͨ¹ýshow databases;ÃüÁîÏÔʾËùÓÐÒÑ´´½¨µÄÊý¾Ý¿âµÄÃû³Æ¡£
ͨ¹ýcreate database XXX;´´½¨Êý¾Ý¿âÃûΪXXXµÄÊý¾Ý¿â¡£ ÀýÈ磺mysql>create database test;     ¶þ.´´½¨±íµ¥ ͨ¹ýcreate table XXX();´´½¨ ÀýÈç: È»ºó¿ÉÒÔͨ¹ýdescÃüÁî²é¿´±íµ¥: ÀýÈç: Èý ......

mysql ²é¿´Ë÷ÒýʹÓÃÇé¿ö

 ÕâÊÇÒÔ¶ÁΪÖ÷µÄÏßÉÏ¿â
root@read 02:28:07>show status like ‘Handler_read%’; 
+———————–+——-+ 
| Variable_name         | Value | 
+————&m ......

mysqlË÷ÒýµÄÒ»¸ö¼¼ÇÉ

Õë¶Ôselect * from table where col1 > number order by col2 desc¡£
Æäʵ°´ÕÕ³£¹æµÄ·½·¨¿ÉÒÔÕâÑùÉè¼Æ£ºkey(col1, col2)
µ«ÊÇÕâÖÖ°ì·¨ÔÚmysqlÀï²»ËãÊÇÀíÏëµÄ£¬whereÌõ¼þÀïÏÞ¶¨Ë÷Òýǰ²¿·ÖÊÇÒ»¸ö·¶Î§µÄÇé¿öϺóÃæµÄorder by»¹ÊÇ»áÓÐfilesort¡£Èç¹ûwhereÌõ¼þÀïÏÞ¶¨Ë÷Òýǰ²¿·ÖÊÇÒ»¸ö³£Á¿£¬ÄÇôorder by¾Í»áÓÐЧÀûÓÃË÷Òý¡£À ......
© 2009 ej38.com All Rights Reserved. ¹ØÓÚE½¡ÍøÁªÏµÎÒÃÇ | Õ¾µãµØÍ¼ | ¸ÓICP±¸09004571ºÅ