I need to do some comparison through 3 columns containing string dates 'yyyy-mm-dd', in Hive SQL. Please take in consideration that the table has more than 2 million records.

Consider three columns (col1; col2; col3) from table T1, I must guarantee that:

1. col1 = col2, and both, or at least one is different from col3.

My best regards,

CodePudding user response：

Logically you have an issue.

col1 = col2

Therefore if col1 != col3 then col2 != col3;

There for it's really enough to use:

select * from T1 where col1 = col2 and col1 != col3;

It is appropriate to do this map side so using a where criteria is likely good enough.

If you wanted to say 2 out of the 3 need to match you could use group by with having to reduce comparisons.