Guangning Yu's Blog

• Date functions

-- change date format
from_unixtime(unix_timestamp('20150101' ,'yyyyMMdd'), 'yyyy-MM-dd')
-- add n days
date_add('2015-11-01', 30)  -- will return '2015-12-01'
-- calculate date difference
datediff('2015-12-01', '2015-11-01') -- will return 30

• Generate row number

row_number() over (DISTRIBUTE BY... SORT BY... DESC)

• Get partition information

analyze table xxx.yyy partition(dt = '2015-12-11') compute statistics;
describe formated xxx.yyy partition (dt = '2015-12-11');