SELECT NAME,GRADE,SHIJIAN,to_char(SHIJIAN,'hh24') as 时,to_char(SHIJIAN,'mi') as 分, to_char(SHIJIAN,'ss') as 秒 FROM STU_01 order by to_char(SHIJIAN,'hh24') DESC;
更改记录:(可以一次性更改同一条记录中的多个字段的内容)
UPDATE STU_01 SET AGE =17,SHIJIAN = to_timestamp('2021-10-05 19:13:15','yyyy-mm-ddhh24:mi:ss') WHERE Name = '小明';
SELECT NAME,AGE,SHIJIAN FROM STU_01;