[FLINK-3723] Aggregate Functions and scalar expressions shouldn't be mixed in select

• Type: Improvement
• Status: Closed
• Priority: Critical
• Resolution: Won't Fix
• Affects Version/s: 1.0.1
• Component/s: Table SQL / API
• Assignee: Unassigned
• Reporter: Yijie Shen
• Created: 10/Apr/16 09:07
• Updated: 16/Nov/17 10:28
• Resolved: 16/Nov/17 10:28

Description

When we type

select deptno, name, max(age) from dept group by deptno;

in calcite or Oracle, it will complain

Expression 'NAME' is not being grouped

or

Column 'dept.name' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

because of the nondeterministic result.

Therefore, I suggest to separate the current functionality of `select` into two api, the new `select` only handle scalar expressions, and an `agg` accept Aggregates.

def select(exprs: Expression*)
def agg(aggs: Aggregation*)
....

tbl.groupBy('deptno)
   .agg('age.max, 'age.min)