ORA-01861: 文字与格式字符串不匹配---解决办法

往oracle中插入时间  '2007-12-28 10:07:24'
如果直接按照字符串方式，或者，直接使用to_date('2007-12-28 10:07:24'）,没有指定日期格式，就会报错：ORA-01861: 文字与格式字符串不匹配
必须指定日期格式 
to_date('2007-12-28 10:07:24' , 'yyyy-mm-dd hh24:mi:ss')

/* Formatted on 2019/10/10 09:17:55 (QP5 v5.252.13127.32847) */
SELECT    TO_CHAR (TO_DATE ('2019-10-10', 'yyyy-mm-dd'), 'YY')
       || (CASE
              WHEN TO_CHAR (
                      NEXT_DAY (TO_DATE ('2019-10-10', 'yyyy-mm-dd'),
                                '星期日'),
                      'YYYY') <>
                      TO_CHAR (TO_DATE ('2019-10-10', 'yyyy-mm-dd'), 'YYYY')
              THEN
                 '01'
              WHEN TO_CHAR (TO_DATE ('2019-10-10', 'yyyy-mm-dd'), 'D') = '1'
              THEN
                 TO_CHAR (TO_DATE ('2019-10-10', 'yyyy-mm-dd') + 1, 'IW')
              ELSE
                 TO_CHAR (TO_DATE ('2019-10-10', 'yyyy-mm-dd'), 'IW')
           END)
          AS YearWeek
  FROM DUAL