oracl 和db2 常用语法比较： 1、取前N条记录 Oracle：Select * from TableName where rownum <= N; DB2：Select * from TableName fetch first N rows only; 2、取得系统日期 Oracle：Select sysdate from dual; DB2：Select current timestamp from sysibm.sysdummy1; 3、空值转换 Oracle：Select
这个项目希望能把帮大家提升实力！启动 Postfix服务
输入命令metc/ postfix/main. cf打开 maincf文件并找到下图内容
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