Symbols - Aster Analytics

Teradata Aster® Analytics Foundation User GuideUpdate 2

Aster Analytics
Release Number
September 2017
English (United States)
Last Update
Product Category

A Symbol is a label or identifier that identifies a row in the Pattern and Result arguments. A Symbol can be any valid identifier (that is, a sequence of characters and digits that begins with a character) but is typically one or two uppercase letters. Symbols are case-insensitive; that is, 'SU' is identical to 'su', and the system reports an error if you use both.

For example, suppose that you have this input table:

record city temp rh cloudcover windspeed winddirection rained_next_day
1 Tuscson 81 30 0.0 5 NW 1
2 Tempe 76 40 0.2 15 NE 0
3 Tuscson 70 70 0.4 10 N 0
4 Tusayan 75 50 0.4 5 NW 0

This table has examples of symbol definitions and the rows of the table that they match in NONOVERLAPPING mode:

Symbol Definition Rows Matched
temp >= 80 AS H 1
winddirection = 'NW' AS NW 1, 4
winddirection = 'NW' OR windspeed > 12 AS W 1, 2, 4
cloudcover != 0.0 AND rh > 35 AS C 2, 3, 4

(An alternative to != is <>.)

'true' AS A 1, 2, 3, 4

This symbol definition matches all rows, for any input table.

city like 'tu%' AS TU None

The like operator is case-sensitive. The % operator matches any number of characters.

city not like 'tu%' AS TU None
city ilike 'tu%' AS TU 1, 3, 4

The ilike operator is case-insensitive.

city not ilike 'tu%' AS N 2
city ilike 'tu%n' as T 1, 3, 4

The % operator matches any number of characters.

city ilike 'tu___n' as T 1, 3

The underscore (_) operator matches any single character. The pattern 'tu___n' has three underscores, so it matches 'Tucson' but not 'Tusayan'.

Rows with NULL values do not match any symbol. That is, the function ignores rows with missing values.