There is no primary key in hive, we can use "describe formatted table_name" to check the fields of a table.
sysdate(-1)  returns the date of yesterday
sysdate( 0)  returns the date of today
sysdate( 1)  returns the date of tomorrow
Use "group by" instead of "distinct".
Always remember using dp/dt to select partitions to improve the efficiency.

Use select * from table_name limit 10 to check it out firstly.

Use SHOW PARTITIONS table_name to check the partitions.