For 0.2 release, the lag function does not work about sqlwindowing

[hbutani]

Ok will take look tomorrow.
Thanks for being patient and continuing to test. Glad the rank function finally works.
Will take at the null value issue.

[hbutani]

There were 2 issues with the query:

• you had 'r' in the select
• you have to explicitly specify the datatype of the expression, if you don't it assumes it is a double.

The query needed to be:
from emp
partition by department_id
order by department_id, salary desc
select department_id, employee_id, salary,
< lag('salary',1) - salary > as salary_gap[int]
into path='/tmp/wout';

But:

• should have given you an error message about the job failing; in fact in this case should have caught the issue in the parser. I am looking at this issue.
• should automatically cast from int to double; will look into this issue also

[hbutani]

I have fixed couple of the issues:

• check for unknown columns in select list
• expose errors in MR job on console; you should see a FAIL status and message about the failure.

Have not fixed the issue about specifying the datatype explicitly. I want to first add code to analyze Groovy expressions to infer the datatype of an expression. Just adding datatype conversion to the engine to convert to the datatype of the output column may add a lot of overhead. Let me think about this.

[java8964]

OK. So I have to specify the type, in fact, the salary column is a double type column.

Any way, the following query works as I expected:

from employees
partition by department_id
order by department_id, salary desc
select department_id, employee_id, salary,
< lag('salary',1) > as salary_pre[double]
into path='/tmp/wout'

But I am not sure why the first_value function is not working. When I run the following query, no error, but still, not final file is generated in /tmp/wout:

from employees
partition by department_id
order by department_id, salary desc
select department_id, employee_id, salary,
< first_value('salary') > as high_salary[double]
into path='/tmp/wout'

Both queries are almost the same, except using different functions

[hbutani]

first_value needs to be used in a windowing clause; so your query should be written as

from employees
partition by department_id
order by department_id, salary desc
with
first_value('salary') as high_salary
select department_id, employee_id, salary, high_salary

Lead and Lag are usable in both windowing clauses and in select statements. In select statements you can use them to do delta computations, ratios etc. These are calculations that happen on the output after the windowing clauses are computed.

• yes since salary is double a lag expression shouldn't have to specify the type. I'm working on this.
• I haven't uploaded a new jar with the changes that print out the FAIL status. Let me do this. You will have to replace your jar with this new one.

[java8964]

Thanks. The first_value works fine. I will close this issue.