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
decode的几种用法
1:使用decode判断字符串是否一样
DECODE(value,if1,then1,if2,then2,if3,then3,…,else)
含义为
IF 条件=值1 THEN
RETURN(value 1)
ELSIF 条件=值2 THEN
RETURN(value 2)
……
ELSIF 条件=值n THEN
RETURN(value 3)
ELSE
RETURN(default)
END IF
sql测试
sel