Oracle 获取年份的最后一周

create or replace function udf_year_lastweek(
i_year varchar2 – 年。如2015
) return varchar2
is

v_year varchar2(6) ;
v_date_temp VARCHAR(8);
begin
v_date_temp:= (substr(i_year,1,4)||‘1231’);

SELECT 
		    substr(MAX(swt.WEEK_ID),1,6) 
INTO 
			v_year 
FROM s_week_time swt 
WHERE swt.START_DATE<= v_date_temp ;

-- =========================== 结果返回 ===========================
RETURN v_year;

end udf_year_lastweek;
/