This commit fix the issue [ISSUE-2002].
It changes the priority of coalesce, ifnull, nullif function etc.
The priority of decimal is higher then varchar in the IS_SUPERTYPE_OF compare mode.
Example:
select coalesce(decimal_column, 1) from table;
the return type of coalesce should be decimal instead of varchar.
Add supertype about datetime and date
The supertype of datetime is bigint, largeint etc.
In IS_SUPERTYPE_OF compare mode, the function(bigint, bigint, bigint) is a supertype of function(datetime, bigint, int).
Example:
select coalesce(now(), 1)) from web_returns;
the return type of coalesce should be bigint instead of varchar.
3f325e001a