ts.last() | Teradata R Package - 17.00 - ts.last() - Teradata R Package

Teradata® R Package User Guide

prodname
Teradata R Package
vrm_release
17.00
created_date
November 2020
category
User Guide
featnum
B700-4005-090K

The aggregate function ts.last() returns the newest value, determined by timecode, for each group.

In the event of a tie, such as simultaneous timecode values for a particular group, all tied results are returned. If a sequence number is present with the data, it can break a tie, assuming it is unique across identical timecode values.

ts.last() uses the argument "value.expression" to specify the column for which newest value of the group is to be returned.

  • This function is valid only on columns with numeric types.
  • Nulls are not included in the result computation.

Example 1: Get the newest value of the 'temperature' column of sequenced PTI table

  • Get the newest value.
    > df_seq_last <- df_seq_grp %>% summarise(last_temp = ts.last(temperature))
  • Print the results.
    > df_seq_last %>% arrange(TIMECODE_RANGE, buoyid, last_temp)
    # Source:     lazy query [?? x 4]
    # Database:   [Teradata 16.20.50.01] [Teradata Native Driver 17.0.0.2]
    #   [TDAPUSER@<hostname>/TDAPUSERDB]
    # Ordered by: TIMECODE_RANGE, buoyid, last_temp
      TIMECODE_RANGE                                    `GROUP BY TIME(MINUTES(~ buoyid last_temp
      <chr>                                             <int64>                   <int>     <int>
    1 2014-01-06 08:00:00.000000+00:00,2014-01-06 08:3~ 35345                         0       100
    2 2014-01-06 09:00:00.000000+00:00,2014-01-06 09:3~ 35347                         1        79
    3 2014-01-06 10:00:00.000000+00:00,2014-01-06 10:3~ 35349                        44        43
    4 2014-01-06 10:30:00.000000+00:00,2014-01-06 11:0~ 35350                        22        23
    5 2014-01-06 10:30:00.000000+00:00,2014-01-06 11:0~ 35350                        44        43
    6 2014-01-06 21:00:00.000000+00:00,2014-01-06 21:3~ 35371                         2        82

Example 2: Get the newest value of the 'temperature' column of non-PTI table

  • Get the newest value.
    > df_nonpti_last <- df_nonpti_grp %>% summarise(last_temp = ts.last(temperature))
  • Print the results.
    > df_nonpti_last %>% arrange(TIMECODE_RANGE, last_temp)
    # Source:     lazy query [?? x 3]
    # Database:   [Teradata 16.20.50.01] [Teradata Native Driver 17.0.0.2]
    #   [TDAPUSER@<hostname>/TDAPUSERDB]
    # Ordered by: TIMECODE_RANGE, last_temp
       TIMECODE_RANGE                                          `GROUP BY TIME(MINUTES(~ last_temp
       <chr>                                                   <int64>                      <int>
     1 2014-01-06 08:00:00.000000+00:00,2014-01-06 08:01:00.0~ 23149921                        10
     2 2014-01-06 08:01:00.000000+00:00,2014-01-06 08:02:00.0~ 23149922                        10
     3 2014-01-06 08:02:00.000000+00:00,2014-01-06 08:03:00.0~ 23149923                        10
     4 2014-01-06 08:03:00.000000+00:00,2014-01-06 08:04:00.0~ 23149924                        10
     5 2014-01-06 08:04:00.000000+00:00,2014-01-06 08:05:00.0~ 23149925                        10
     6 2014-01-06 08:05:00.000000+00:00,2014-01-06 08:06:00.0~ 23149926                        10
     7 2014-01-06 08:06:00.000000+00:00,2014-01-06 08:07:00.0~ 23149927                        10
     8 2014-01-06 08:07:00.000000+00:00,2014-01-06 08:08:00.0~ 23149928                        10
     9 2014-01-06 08:08:00.000000+00:00,2014-01-06 08:09:00.0~ 23149929                        NA
    10 2014-01-06 08:09:00.000000+00:00,2014-01-06 08:10:00.0~ 23149930                        99
    # ... with more rows