[TAJO-1265] min(), max() does not handle null properly

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.10.0
• Assignee: Keuntae Park
• Reporter: Keuntae Park
• Created: 22/Dec/14 05:14
• Updated: 09/Jan/15 06:33
• Resolved: 09/Jan/15 06:33

Description

In other DBs like oracle and postgreSQL,
null is excluded from calculation of min() and max() value until there is no non-null value in the given column, in which case, it returns null.
However, current implementation of Tajo considers null as
0 for int or long column, 0.0 for float or double column, or "" for text column.
It needs to handle null value separately from non-null values in min() and max() calculation.