SQL 语句

  • UPDATE SALARIES set sex = (case when sex = 'f' then 'm' else 'f' end);
  • CREATE UNIQUE INDEX inbound_request_idx_1 ON pmtacpt_inbound_request(merchant_request_id,merchant_account);
    1. 唯一索引，联合索引
    2. 幂等实现方式之一

Orcale

  • select segment_name,segment_type,bytes/1024/1024 from user_segments;

    1. 查看数据库表的大小

  • Alter session set NLS_DATE_FORMAT = 'dd-Mon-yyyy hh24:mi:ss';

    • 修改当前会话的默认date格式

  • Date/String 转换
    http://www.cnblogs.com/reborter/archive/2008/11/28/1343195.html

  • XML字符串操作

    1. extract(xmltype(snapshot_data), '/Root/ABC[@name=''def'']/@value').getNumberVal() columnName

       <Root subject="a">
   <ABC name="def" value="-1.64"/>
   <ABC name="ghi" value="11.99"/>
 </Root >

  • replace(str,'a','b')

  • cast

    1. select cast(max(updatedate) as date) from xx;