MYSQL Ïà¹Ø
MYSQL where id inÎÊÌâ
SELECT * from product WHERE id IN (‘1522,1523,1524′)ORDER BY id DESC
ÔÚMYSQLÀïÃæÖ´ÐÐÕâ¸öÓï¾äÖ»·µ»Ø1522µÄÖµ¡£
Ö´ÐÐ
SELECT * from product WHERE instr(‘1522,1523,1524′,id) ORDER BY id DESC
»òÕß
SELECT * from product WHERE instr(‘1522,1523,1524′,id)>0 ORDER BY id DESC
Ïà¹ØÎĵµ£º
Oracle,MySQL,MSSQL ServerºÍAccessÊý¾Ý¿âµÄͳ¼Æº¯Êý
ÎÒÃÇÔÚ±à³ÌÖг£ÓõÄͳ¼Æº¯ÊýÓмÆÊý,ÇóºÍ,Çó×î´óÖµ,Çó×îСֵ,Ç󯽾ù,·½²îºÍ±ê×¼²î.
·½²î(Variance)
·½²îÊDZê׼ƫ²îµÄƽ·½¡£×éÖеÄÖµ£¬ÓëËüÃÇÆ½¾ùÖµÖ®¼äÆ«Àë³Ì¶ÈµÄ¶ÈÁ¿¡£
±ê׼ƫ²î(Standard Deviation)
Ò»¸ö²ÎÊý£¬Ö¸³öÒ»ÖÖ·½Ê½£¬Ò»¸ö¸ÅÂʺ¯ÊýÒÔÕâÖÖ·½Ê½·Ö²¼ÔÚÆ½¾ùÖµ¸ ......
ÊÔÑé1
ÊÂÎñ1£º
#!/usr/bin/python
import time
import MySQLdb;
conn = MySQLdb.connect(host="localhost",port=3306,user="root",passwd="asdf",db="test",unix_socket="/data/mysql_3306/mysql.sock")
cursor = conn.cursor()
cursor.execute("select * from test")
while str!="1":
str = r ......
truncate table Çå¿Õ±í£¬ºÍdeleteÏàËÆ£¬µ«ÊÇÔÚ±í·Ç³£´óµÄʱºò£¬ËüÊÇÖð²½Êͷŵġ£
insert Èç¹ûÔÚ²åÈëʱ£¬Ä³¸ö×ֶδæÔÚ£¬ÎÒÏë¸üпÉÒÔͨ¹ý insert into tablename values() on duplicate key update id=id+1;
insert into tablename values(default) ĬÈÏ×ÔÔö³¤
select last_insert_id() È¡×îºó²åÈëÒ»Ìõ¡£ ......
Query Cache ÔÚÌá¸ßÊý¾Ý¿âÐÔÄÜ·½Ãæ¾ßÓзdz£ÖØÒªµÄ×÷Óá£
ÆäÉ趨Ҳ·Ç³£¼òµ¥£¬½öÐèÒªÔÚÅäÖÃÎļþдÈëÁ½ÐУº query_cache_type ºÍ query_cache _size£¬¶øÇÒ MySQL µÄ query cache ·Ç³£¿ì£¡¶øÇÒÒ»µ©ÃüÖУ¬¾ÍÖ±½Ó·¢Ë͸ø¿Í»§¶Ë£¬½ÚÔ¼´óÁ¿µÄ CPU ʱ¼ä¡£
µ±È»£¬·Ç SELECT Óï¾ä¶Ô»º³åÊÇÓÐÓ°ÏìµÄ£¬ËüÃÇ¿ÉÄÜʹ»º³åÖеÄÊý¾Ý¹ýÆÚ¡£Ò»¸ö ......
ÉÏÆªÎÒÃÇѧ»áÁËÈçºÎ´´½¨Ò»¸öÊý¾Ý¿âºÍÊý¾Ý¿â±í£¬²¢ÖªµÀÈçºÎÏòÊý¾Ý¿â±íÖÐÌí¼Ó¼Ç¼¡£
ÄÇôÎÒÃÇÈçºÎ´ÓÊý¾Ý¿â±íÖмìË÷Êý¾ÝÄØ£¿
1¡¢´ÓÊý¾Ý¿â±íÖмìË÷ÐÅÏ¢
ʵ¼ÊÉÏ£¬Ç°ÃæÎÒÃÇÒѾÓõ½ÁËSELECTÓï¾ä£¬ËüÓÃÀ´´ÓÊý¾Ý¿â±íÖмìË÷ÐÅÏ¢¡£
selectÓï¾ä¸ñʽһ°ãΪ£º
SELECT ¼ìË÷¹Ø¼ü´Ê from ±»¼ìË÷µÄ±í WHERE ¼ìË÷Ìõ¼þ( ......