[KYLIN-3359] Support sum(expression) if possible

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: v2.4.0
• Component/s: Query Engine
• Assignee: Zhong Yanghong
• Reporter: Zhong Yanghong
• Created: 02/May/18 10:19
• Updated: 09/Sep/20 00:57
• Resolved: 15/Jun/18 05:58

Description

The expression can be as follows:

1. a ₁*col ₁ + a ₂*col ₂ + ... + a _n*col _n + b, if sum(col ₁),sum(col ₂),...sum(col _n) are defined
2. case when filter ₁ then expr ₁
   when filter ₂ then expr ₂
   ...
   else expr _N
   end, if filter ₁,filter ₂, ... filter _N-1, and expr ₁,expr ₂,...expr _N are supported

There's a constraint for the filter. That is it's able to push down the related filters in case when.

Issue Links

• is duplicated by: KYLIN-793 Count(COL) should exclude null value rows
• is duplicated by: KYLIN-2948 Count a column returns the same result as count(*) even if this column has NULL
• is related to: KYLIN-2049 Incorrect AVG result with NULL measure values
• is related to: KYLIN-4620 sum(expression) support should be limited since it's not conform the associative law of addition in standard sql
• relates to: KYLIN-2341 sum(case .. when ..) is not supported