mysql使用索引最佳化order排序,mysqlorder 個人原創地址:http://www.phpthinking.com/archives/433在資料庫中我們一般都會對一些欄位進行索引操作,這樣可以提升資料的查詢速度,同時提高資料庫的效能像order by ,group by前都需要索引。先我們要注意一下1>mysql一次查詢只能使用一個索引。如果要對多個欄位使用索引,建立複合索引。2>在ORDER
Tracing datapump sessions,tracingdatapumpTracing datapump is not straight forward, you can trace the datapump worker(dw00) or datapump master(DM00) with 10046 to get the sql etc or use the TRACE option in expdp/impdpWhere in expdp has an
Mysql 大量刪除首碼或者尾碼表,mysql大量刪除oracl有drop table like 的用法,但是mysql沒有,可以寫指令碼(不做贅述),也可以組裝sql。注意,我的資料庫名字是test,有個表叫data,然後我準備四個有相同首碼的表,大量刪除,準備資料可以用這條sqlCREATE TABLE test_1201 SELECT * FROM `data`;CREATE TABLE test_1202 SELECT * FROM `data`;CREATE TABLE test_12
IT忍者神龜之date日期回顧,it忍者神龜dateCalendar cal = Calendar.getInstance();cal.get(Calendar.DAY_OF_MONTH);cal.get(Calendar.MONTH);cal.get(Calendar.YEAR);SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMdd&q
【MonogoDB】The high update operation of MongoDB,monogodbmongodbIn the last four blog, we talked about the high query operation of mongodb. Now in this blog let's know about the high update operation about monodb.1. Saveas for save(), whose function
賬戶別名接收交易處理,賬戶別名交易處理--賬戶別名接收SELECT mtl_material_transactions_s.nextval INTO l_mtl_txn_itf_rec.transaction_interface_id FROM dual;l_mtl_txn_itf_rec.transaction_header_id :=