oracle常用函数介绍

Posted 2020-09-26 H.U.C-王子

字符函数

数学函数

日期函数

转换函数

to_char(数字/日期)是把日期或数字转换为字符串

• 将数字转换成指定格式
• 

• to_char(1210.73, \'9999.9\')           -- would return \'1210.7\'
  to_char(1210.73, \'9,999.99\')      -- would return \'1,210.73\'
  to_char(1210.73, \'$9,999.00\')   --  would return \'$1,210.73\'
  to_char(21, \'000099\')           -- would return \'000021\'

• 将日期转换成指定格式
• 

  to_char(sysdate, \'yyyy/mm/dd\');--would return \'2003/07/09\'
  select to_char(sysdate, \'yyyy-mm-dd  hh24:mi:ss\')  from a;    ------> 2015-08-28  14:43:15
  select to_char(sysdate, \'yyyy-mm-dd  hh12:mi:ss\')  from a;    ------> 2015-08-28  02:43:15
  to_char(sysdate, \'yyyy/mm/dd\');--would return \'2003/07/09\'
  to_char(sysdate,\'dd-mm-yyyy\')--按dd-mm-yyyy格式转换23-05 -2016
  to_char(sysdate, \'Month DD, YYYY\');--would return \'10月 21, 2015\'
  to_char(sysdate, \'FMMonth DD, YYYY\');--would return \'July 9, 2003\'
  to_char(sysdate, \'MON DDth, YYYY\');--would return \'JUL 09TH, 2003\'
  to_char(sysdate, \'FMMON DDth, YYYY\');--would return \'JUL 9TH, 2003\'
  to_char(sysdate, \'FMMon ddth, YYYY\');--would return \'Jul 9th, 2003\'
  to_char(sysdate, \'FMMonth DD, YYYY\');--would return \'July 9, 2003\'
  to_char(sysdate, \'FMMON DDth, YYYY\');--would return \'JUL 9TH, 2003\'
  to_char(sysdate, \'FMMon ddth, YYYY\');--would return \'Jul 9th, 2003\'

to_number(字符串)  将给出的字符转换为数字

select to_number(\'123\') from a ;  

常规函数