判定一个字符串是否为有效时间的函数

CREATE OR REPLACE FUNCTION is_date(parameter VARCHAR2) RETURN NUMBER ISval DATE;BEGINval := TO_DATE(NVL(parameter, 'a'), 'yyyy-mm-dd hh24:mi:ss');RETURN 1;EXCEPTIONWHEN OTHERS THENRETURN 0;END;

alter session force parallel ddl parallel 8;create table TT as select t.id,floor(months_between(sysdate,to_date(t.birthday,'yyyymmdd'))/12) agefrom TT_WXTRAN twhere is_date(t.birthday)!=0;