address comments

Author: yaooqinn

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/datetimeExpressions.scala

@@ -2134,33 +2134,7 @@ object DatePartLike {
   usage = "_FUNC_(field, source) - Extracts a part of the date/timestamp or interval source.",
   arguments = """
     Arguments:
-      * field - selects which part of the source should be extracted.
-          - Supported string values of `field` for dates and timestamps are:
-              - "MILLENNIUM", ("MILLENNIA", "MIL", "MILS") - the conventional numbering of millennia
-              - "CENTURY", ("CENTURIES", "C", "CENT") - the conventional numbering of centuries
-              - "DECADE", ("DECADES", "DEC", "DECS") - the year field divided by 1
-              - "YEAR", ("Y", "YEARS", "YR", "YRS") - the year field
-              - "ISOYEAR" - the ISO 8601 week-numbering year that the datetime falls in
-              - "QUARTER", ("QTR") - the quarter (1 - 4) of the year that the datetime falls in
-              - "MONTH", ("MON", "MONS", "MONTHS") - the month field
-              - "WEEK", ("W", "WEEKS") - the number of the ISO 8601 week-of-week-based-year. A week is considered to start on a Monday and week 1 is the first week with >3 days. In the ISO week-numbering system, it is possible for early-January dates to be part of the 52nd or 53rd week of the previous year, and for late-December dates to be part of the first week of the next year. For example, 2005-01-02 is part of the 53rd week of year 2004, while 2012-12-31 is part of the first week of 2013
-              - "DAY", ("D", "DAYS") - the day of the month field (1 - 31)
-              - "DAYOFWEEK",("DOW") - the day of the week for datetime as Sunday(1) to Saturday(7)
-              - "ISODOW" - ISO 8601 based day of the week for datetime as Monday(1) to Sunday(7)
-              - "DOY" - the day of the year (1 - 365/366)
-              - "HOUR", ("H", "HOURS", "HR", "HRS") - The hour field (0 - 23)
-              - "MINUTE", ("M", "MIN", "MINS", "MINUTES") - the minutes field (0 - 59)
-              - "SECOND", ("S", "SEC", "SECONDS", "SECS") - the seconds field, including fractional parts
-              - "MILLISECONDS", ("MSEC", "MSECS", "MILLISECON", "MSECONDS", "MS") - the seconds field, including fractional parts, multiplied by 1000. Note that this includes full seconds
-              - "MICROSECONDS", ("USEC", "USECS", "USECONDS", "MICROSECON", "US") - The seconds field, including fractional parts, multiplied by 1000000. Note that this includes full seconds
-              - "EPOCH" - the number of seconds with fractional part in microsecond precision since 1970-01-01 00:00:00 local time (can be negative)
-          - Supported string values of `field` for interval(which consists of `months`, `days`, `microseconds`) are:
-              - "YEAR", ("Y", "YEARS", "YR", "YRS") - the total `months` / 12
-              - "MONTH", ("MON", "MONS", "MONTHS") - the total `months` modulo 12
-              - "DAY", ("D", "DAYS") - the `days` part of interval
-              - "HOUR", ("H", "HOURS", "HR", "HRS") - how many hours the `microseconds` contains
-              - "MINUTE", ("M", "MIN", "MINS", "MINUTES") - how many minutes left after taking hours from `microseconds`
-              - "SECOND", ("S", "SEC", "SECONDS", "SECS") - how many second with fractions left after taking hours and minutes from `microseconds`
+      * field - selects which part of the source should be extracted, and supported string values are as same as the fields of the equivalent function `EXTRACT`.
       * source - a date/timestamp or interval column from where `field` should be extracted
   """,
   examples = """
@@ -2179,7 +2153,7 @@ object DatePartLike {
        30.001001
   """,
   note = """
-    The _FUNC_ function is equivalent to the SQL-standard function `extract`
+    The _FUNC_ function is equivalent to the SQL-standard function `EXTRACT(field FROM source)`
   """,
   since = "3.0.0")
 // scalastyle:on line.size.limit
@@ -2200,8 +2174,33 @@ case class DatePart(field: Expression, source: Expression, child: Expression)
   usage = "_FUNC_(field FROM source) - Extracts a part of the date/timestamp or interval source.",
   arguments = """
     Arguments:
-      * field - selects which part of the source should be extracted and supported string values
-                are the same with the `date_part` fields.
+      * field - selects which part of the source should be extracted
+          - Supported string values of `field` for dates and timestamps are:
+              - "MILLENNIUM", ("MILLENNIA", "MIL", "MILS") - the conventional numbering of millennia
+              - "CENTURY", ("CENTURIES", "C", "CENT") - the conventional numbering of centuries
+              - "DECADE", ("DECADES", "DEC", "DECS") - the year field divided by 10
+              - "YEAR", ("Y", "YEARS", "YR", "YRS") - the year field
+              - "ISOYEAR" - the ISO 8601 week-numbering year that the datetime falls in
+              - "QUARTER", ("QTR") - the quarter (1 - 4) of the year that the datetime falls in
+              - "MONTH", ("MON", "MONS", "MONTHS") - the month field (1 - 12)
+              - "WEEK", ("W", "WEEKS") - the number of the ISO 8601 week-of-week-based-year. A week is considered to start on a Monday and week 1 is the first week with >3 days. In the ISO week-numbering system, it is possible for early-January dates to be part of the 52nd or 53rd week of the previous year, and for late-December dates to be part of the first week of the next year. For example, 2005-01-02 is part of the 53rd week of year 2004, while 2012-12-31 is part of the first week of 2013
+              - "DAY", ("D", "DAYS") - the day of the month field (1 - 31)
+              - "DAYOFWEEK",("DOW") - the day of the week for datetime as Sunday(1) to Saturday(7)
+              - "ISODOW" - ISO 8601 based day of the week for datetime as Monday(1) to Sunday(7)
+              - "DOY" - the day of the year (1 - 365/366)
+              - "HOUR", ("H", "HOURS", "HR", "HRS") - The hour field (0 - 23)
+              - "MINUTE", ("M", "MIN", "MINS", "MINUTES") - the minutes field (0 - 59)
+              - "SECOND", ("S", "SEC", "SECONDS", "SECS") - the seconds field, including fractional parts
+              - "MILLISECONDS", ("MSEC", "MSECS", "MILLISECON", "MSECONDS", "MS") - the seconds field, including fractional parts, multiplied by 1000. Note that this includes full seconds
+              - "MICROSECONDS", ("USEC", "USECS", "USECONDS", "MICROSECON", "US") - The seconds field, including fractional parts, multiplied by 1000000. Note that this includes full seconds
+              - "EPOCH" - the number of seconds with fractional part in microsecond precision since 1970-01-01 00:00:00 local time (can be negative)
+          - Supported string values of `field` for interval(which consists of `months`, `days`, `microseconds`) are:
+              - "YEAR", ("Y", "YEARS", "YR", "YRS") - the total `months` / 12
+              - "MONTH", ("MON", "MONS", "MONTHS") - the total `months` % 12
+              - "DAY", ("D", "DAYS") - the `days` part of interval
+              - "HOUR", ("H", "HOURS", "HR", "HRS") - how many hours the `microseconds` contains
+              - "MINUTE", ("M", "MIN", "MINS", "MINUTES") - how many minutes left after taking hours from `microseconds`
+              - "SECOND", ("S", "SEC", "SECONDS", "SECS") - how many second with fractions left after taking hours and minutes from `microseconds`
       * source - a date/timestamp or interval column from where `field` should be extracted
   """,
   examples = """
@@ -2220,7 +2219,7 @@ case class DatePart(field: Expression, source: Expression, child: Expression)
        30.001001
   """,
   note = """
-    The _FUNC_ function is equivalent to `date_part`.
+    The _FUNC_ function is equivalent to `date_part(field, source)`.
   """,
   since = "3.0.0")
 // scalastyle:on line.size.limit