SQL中日期与字符串互相转换操作实例

select      to_char(sysdate, "yyyy") || "年"    || to_char(sysdate, "mm") || "月"    || to_char(sysdate, "dd") || "日"   || " "   || to_char(sysdate, "hh24") || "時"    || to_char(sysdate, "mi") || "分"    || to_char(sysdate, "ss") || "秒" from  dual

select  to_char(sysdate, "yyyy-mm-dd hh24:mi:ss") from  dual

select  to_char(sysdate, "yyyyfm-mm-dd hh24:mi:ss") from  dual

select  to_char(sysdate, "yyyy/mm/dd") from  dual

select  to_char(sysdate, "yyyymmdd") from  dual

select  to_date("20210908", "yyyymmdd") from  dual

select  to_date("2021-9-8 11:21:55", "yyyyfm-mm-dd hh24:mi:ss") from  dual

SELECT  CONVERT(varchar (100), GETDATE(), 111)

SELECT  CONVERT(varchar (100), GETDATE(), 23)

SELECT  CONVERT(varchar (100), GETDATE(), 112)

SELECT  CONVERT(varchar (100), GETDATE(), 120)

select    CONVERT(varchar, DATEPART(yy, GETDATE())) + "年"   + CONVERT(varchar, DATEPART(mm, GETDATE())) + "月"   + CONVERT(varchar, DATEPART(dd, GETDATE())) + "日"

SELECT  CAST("20200908" as datetime)

SELECT  CAST("20200908" as date)

SELECT   TRY_CAST("2021-09-08" as datetime)

SELECT   TRY_CAST("2021/09/08 11:21:55" as datetime)

SELECTDATE_FORMAT(NOW(), "%Y年%m月%d日 %H时%i分%s秒" );

SELECTDATE_FORMAT(NOW(), "%Y-%m-%d %H:%i:%s")

SELECTSTR_TO_DATE("2019年01月17日 19时05分05秒", "%Y年%m月%d日 %H时%i分%s秒");