mysql語(yǔ)句中使用like后面的%（百分號(hào)）的問(wèn)題_MySQL教程

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1.安裝安裝mysqlconnector2.配置mysqlconnectorODBC數(shù)據(jù)管理器-系統(tǒng)DSN-添加-mysql ODBC 5.3 ANSI driver-填入data source name如jt,mysql的ip、用戶(hù)名、密碼即可3.新建鏈接服務(wù)器exec sp_addlinkedserver@server='jt', --ODBC里面data source name@srvproduct='mysql'

 　　問(wèn)題：mysql語(yǔ)句中使用like后面的%(百分號(hào)) 是不是越多執(zhí)行效率越慢!

　　總用時(shí)：0.0489秒 0.0691 0.0485 0.0467

　　SELECT `goods_name`, `goods_img`, `sku_id`, `import` FROM `goods` WHERE `goods_name` LIKE '%iPhone%iPod%' AND `stime` < 1413877244 AND `etime` > 1413877244 ORDER BY `flag` DESC

　　總用時(shí)：0.0460秒 0.0430 0.0493 0.0783 0.0496

　　SELECT `goods_name`, `goods_img`, `sku_id`, `import` FROM `goods` WHERE `goods_name` LIKE '%iPhone%' AND `goods_name` LIKE '%iPod%' AND `stime` < 1413877367 AND `etime` > 1413877367 ORDER BY `flag` DESC

　　總用時(shí)：0.0458秒 0.0441秒 0.0449秒

　　SELECT `goods_name`, `goods_img`, `sku_id`, `import` FROM `goods` WHERE `goods_name` LIKE '%%%%%%%%%%%%%%%%%%%%%%%iPhone%iPod%%%%%%%%%%%%%%%%%%%%%%%' AND `stime` < 1413877997 AND `etime` > 1413877997 ORDER BY `flag` DESC

　　實(shí)踐證明，百分號(hào)的數(shù)量不影響sql執(zhí)行的速度。這幾種方法的效率都是差不多的。

　　以上是我測(cè)試的結(jié)果。個(gè)人可根據(jù)自己的實(shí)際需求去選擇寫(xiě)法!建議是最好選擇第二種!

分享：EXP-00091: Exporting questionable statistics
一.出現(xiàn)EXP-00091錯(cuò)誤 [oracle@localhost tmp]$ exp '/ as sysdba' tables=testxuchao.TAB_XN_PY_DICT \ file=/tmp/xifenfei.dmp log=/tmp/xifenfei.log Export: Release 9.2.0.4.0 - Production on Mon Jan 16 16:02:37 2012 Copyright (c) 1982, 2002, Oracle Corpor