Use Sum, Avg etc. Aggregate func to agg field which type was long will added .0 at end of metrics

[Lvnszn]

Bug Report

1. Minimal reproduce step (Required)

SQL:

select sum(count_in) as a from customer_flow_stat limit 100

2. What did you expect to see? (Required)

Double should be Long.

Version: 0.7.0-SNAPSHOT-255202ec4fc7df2283f7c275d8e9025a26cf3274

[Lvnszn]

cc @fx19880617

[xiangfu0]

I was also thinking that we can return a long value if the column is INT or LONG (There could be an issue if the result is larger than LONG.MAX, then the only way to handle it is still DOUBLE).

Or make the cast function work outside the aggregation functions.

[xiangfu0]

Another way is to have functions like SumLong to handle this case.