[TAJO-449] Implement extract() function

• Type: New Feature
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.8.0
• Assignee: Keuntae Park
• Reporter: Keuntae Park
• Created: 23/Dec/13 05:50
• Updated: 23/Jan/14 02:38
• Resolved: 23/Jan/14 02:36

Description

EXTRACT (field FROM source)

it returns field part of source.
source must be a value expression of type timestamp, time, or interval.
For date type, it should be cast to timestamp and used.

field can be:

• century
• day: for timestamp, the day of the month (1 - 31); for interval, the number of days
• decade: the year divided by 10
• dow: the day of the week as Sunday(0) to Saturday(6)
• doy: the day of the year (1 - 365)
• epoch: for timestamp, the number of seconds since 1970-01-01 00:00:00 UTC (can be negative); for interval values, the total number of seconds in the interval
• hour
• isodow: the day of the week as Monday(1) to Sunday(7)
• isoyear: the ISO 8601 year, which begins with the Monday of the week containing the 4th of January, so in early January or late December the ISO year may be different from the Gregorian year.
• microseconds
• millennium
• milliseconds
• minute
• month
• quarter: the quarter of the year (1 - 4)
• second:the seconds field, including fractional parts
• timezone: the time zone offset from UTC, measured in seconds
• timezone_hour: the hour component of the time zone offset
• timezone_minute: the minute component of the time zone offset
• week
• year

Detailed explanation can be found in http://www.postgresql.org/docs/9.1/static/functions-datetime.html