mysql date convertion and column renaming

select curtime(); select current_time();  --current time; hour:min:sec
select current_timestamp();  --show current time stamp:year month date hour:min:sec
select unix_timestamp();   --convert time stamp into unix time: internal of milies second from 1970 year
select from_unixtime();    --convert unix time into time stamp


alter table name change @original  @new type; -- change column name