sql查询列为null显示0

查itemfile表中itemdesc、re_level列的信息，要求re_level为NULL时显示为0，写出相应语句。

Oracle :select itemdesc,nvl(re_level,’0’) from itemfile;
Mysql: select itemdesc,ifnull(re_level,’0’) from itemfile;
SqlServer: select itemdesc,isnull(re_level,'0') from itemfile;