[SPARK-28469][SQL] Change CalendarIntervalType's readable string representation from calendarinterval to interval

[wangyum]

What changes were proposed in this pull request?

This PR change CalendarIntervalType's readable string representation from calendarinterval to interval.

How was this patch tested?

Existing UT

[dongjoon-hyun]

Please update the title. Changing name is more important than adding simpleString.

[SparkQA]

Test build #107989 has finished for PR 25225 at commit e84fce8.

• This patch fails due to an unknown error code, -9.
• This patch merges cleanly.
• This patch adds no public classes.

[wangyum]

retest this please

[dongjoon-hyun]

Thank you for updating.

[dongjoon-hyun]

cc @gatorsmile

[SparkQA]

Test build #107994 has finished for PR 25225 at commit e84fce8.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[dongjoon-hyun]

I'm +1 for this changes.

[dongjoon-hyun]

Although PostgreSQL has several variants. In Spark side, we have no such things. So, this will not be misleading. How do you think about this PR, @gatorsmile ?

postgres=# CREATE TABLE T AS SELECT INTERVAL '1' YEAR A, INTERVAL '1' MONTH B, INTERVAL '1' DAY C, INTERVAL '1' HOUR D, INTERVAL '1' MINUTE E, INTERVAL '1' SECOND F, INTERVAL '1 day';
SELECT 1
postgres=# \d T;
                      Table "public.t"
  Column  |      Type       | Collation | Nullable | Default
----------+-----------------+-----------+----------+---------
 a        | interval year   |           |          |
 b        | interval month  |           |          |
 c        | interval day    |           |          |
 d        | interval hour   |           |          |
 e        | interval minute |           |          |
 f        | interval second |           |          |
 interval | interval        |           |          |

[maropu]

+1, too.

fyi: the interval name seems to be specified by SQL-92:

Compatibility: The following types (or spellings thereof) are specified by SQL: bigint, bit, bit varying, boolean, char, character varying, character, varchar, date, double precision, integer, interval, numeric, decimal, real, smallint, time (with or without time zone), timestamp (with or without time zone), xml.

cited from https://www.postgresql.org/docs/9.2/datatype.html

[dongjoon-hyun]

Yep. I think it's okay by itself. Thank you for the pointer.

[dongjoon-hyun]

Merged to master. Thank you, @wangyum and @maropu .
cc @gatorsmile and @cloud-fan

[HyukjinKwon]

+1 too