Oracle 函数

--decode函数替换
update table
   set clumn = DECODE(clumn0,
                          NULL,
                          DECODE(clumn1,
                                 NULL,
                                 DECODE(clumn2,
                                        NULL,
                                        DECODE(clumn3, NULL, NULL, clumn3),
                                        clumn2),
                                 clumn1),
                          clumn0)
 where clumn is null;

--检测字段长度
select * from table where length(clumn)>56