[DRILL-4549] Add support for more truncation units in date_trunc function

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.6.0
• Fix Version/s: 1.7.0
• Assignee: Venki Korukanti
• Reporter: Venki Korukanti
• Reviewer: Khurram Faraaz
• Created: 28/Mar/16 21:22
• Updated: 08/Jun/16 09:37
• Resolved: 29/Mar/16 01:48

Description

Currently we support only YEAR, MONTH, DAY, HOUR, MINUTE, SECOND truncate units for types TIME, TIMESTAMP and DATE. Extend the functions to support YEAR, MONTH, DAY, HOUR, MINUTE, SECOND, WEEK, QUARTER, DECADE, CENTURY, MILLENNIUM truncate units for types TIME, TIMESTAMP, DATE, INTERVAL DAY, INTERVAL YEAR.

Also get rid of the if-and-else (on truncation unit) implementation. Instead resolve to a direct function based on the truncation unit in Calcite -> Drill (DrillOptiq) expression conversion.