data1 |
Required Argument.
Specifies the tbl_teradata containing the input data set.
|
data1.partition.column |
Required Argument.
Specifies Partition By columns for "data1".
Values to this argument can be provided as a vector, if multiple
columns are used for partition.
Types: character OR vector of Strings (character)
|
data1.order.column |
Required Argument.
Specifies Order By columns for "data1".
Values to this argument can be provided as a vector, if multiple
columns are used for ordering.
Types: character OR vector of Strings (character)
|
mode |
Required Argument.
Specifies the pattern-matching mode:
OVERLAPPING: The function finds every occurrence of the pattern in
the partition, regardless of whether it is part of
a previously found match. Therefore, one row can match
multiple symbols in a given matched pattern.
NONOVERLAPPING: The function begins the next pattern search at the
row that follows the last pattern match. This is the
default behavior of many commonly used pattern matching
utilities, including the UNIX grep utility.
Permitted Values: OVERLAPPING, NONOVERLAPPING
Types: character
|
pattern |
Required Argument.
Specifies the pattern for which the function searches. You compose
pattern with the symbols that you define in the symbols argument,
operators, and parentheses. When patterns have multiple operators,
the function applies them in order of precedence, and applies operators
of equal precedence from left to right. To specify that a subpattern must
appear a specific number of times, use the "Range-Matching Feature".
The basic pattern operators in decreasing order of precedence
"pattern", "pattern.", "pattern?", "pattern*", "pattern+",
"pattern1.pattern2", "pattern1|pattern2", "^pattern", "pattern$"
To force the function to evaluate a subpattern first, enclose it in
parentheses.
Example:
^A.(B|C)+.D?.X*.A$
The preceding pattern definition matches any set of rows
whose first row starts with the definition of symbol A,
followed by a non-empty sequence of rows, each of which
meets the definition of either symbol B or C, optionally
followed by one row that meets the definition of symbol D,
followed by any number of rows that meet the definition of
symbol X, and ending with a row that ends with the definition of
symbol A.
You can use parentheses to define precedence rules. Parentheses are
recommended for clarity, even where not strictly required.
Types: character
|
symbols |
Required Argument.
Defines the symbols that appear in the values of the pattern and
result arguments. The col_expr is an expression whose value is a
column name, symbol is any valid identifier, and symbol_predicate is
a SQL predicate (often a column name).
For example, the Symbols argument for analyzing website visits might
look like this:
symbols
(
pagetype = "homepage" AS H,
pagetype <> "homepage" AND pagetype <> "checkout" AS PP,
pagetype = "checkout" AS CO
)
The symbol is case-insensitive; however, a symbol of one or two
uppercase letters is easy to identify in patterns.
If col_expr represents a column that appears in multiple input
tables, then you must qualify the ambiguous column name with its
tbl_teradata name.
For example:
Symbols
(
weblog.pagetype = "homepage" AS H,
weblog.pagetype = "thankyou" AS T,
ads.adname = "xmaspromo" AS X,
ads.adname = "realtorpromo" AS R
)
The mapping from tbl_teradata name to its corresponding SQL name
is as shown below:
data1: input1
data2: input2
data3: input3
You can create symbol predicates that compare a row to a previous
or subsequent row, using a LAG or LEAD operator.
LAG Expression Syntax:
current_expr operator LAG (previous_expr, lag_rows [, default]) |
LAG (previous_expr, lag_rows [, default]) operator current_expr
LAG and LEAD Expression Rules:
A symbol definition can have multiple LAG and LEAD expressions.
A symbol definition that has a LAG or LEAD expression cannot have an OR operator.
If a symbol definition has a LAG or LEAD expression and the input
is not a table, you must create an alias of the input query.
Types:character OR vector of Strings (characters)
|
result |
Required Argument.
Defines the output columns. The col_expr is an expression whose value
is a column name; it specifies the values to retrieve from the
matched rows. The function applies aggregate_function to these
values.
Supported aggregate functions:
SQL aggregate functions are [AVG, COUNT, MAX, MIN, SUM].
ML Engine nPath sequence aggregate functions.
The function evaluates this argument once for every matched pattern
in the partition (that is, it outputs one row for each pattern
match).
Note: For col_expr representing a column that appears in multiple input
tbl_teradata, you must qualify the ambiguous column name with the SQL
name corresponding to its tbl_teradata name. Please see the
description of the "symbols" parameter for the mapping from tbl_teradata
name to the SQL name.
Types:character OR vector of Strings (characters)
|
filter |
Optional Argument.
Specifies filters to impose on the matched rows. The function
combines the filter expressions using the AND operator.
The filter_expression syntax is:
symbol_expression comparison_operator symbol_expression
The two symbol expressions must be type-compatible. The
symbol_expression syntax is:
FIRST | LAST (column_with_expression OF [ANY](symbol[,...]))
The column_with_expression cannot contain the operator AND or OR, and
all its columns must come from the same input. If the function has
multiple inputs, then column_with_expression and symbol must come
from the same input.
The comparison_operator is either <, >, <=, >=, =, or <>.
Note: For column_with_expression representing a column that appears in
multiple input tbl_teradata, you must qualify the ambiguous column
name with the SQL name corresponding to its tbl_teradata name. Please see
the description of the "symbols" parameter for the mapping from
tbl_teradata name to the SQL name.
Types:character OR vector of Strings (characters)
|
data2 |
Optional Argument.
Specifies the additional optional input tbl_teradata containing the
input data set
|
data2.partition.column |
Optional Argument.
Specifies Partition By columns for "data2".
Values to this argument can be provided as a vector, if multiple
columns are used for partition.
Types: character OR vector of Strings (character)
|
data2.order.column |
Optional Argument. Required if "data2" is specified.
Specifies Order By columns for "data2".
Values to this argument can be provided as a vector, if multiple
columns are used for ordering.
Types: character OR vector of Strings (character)
|
data3 |
Optional Argument.
Specifies the additional optional input tbl_teradata containing the
input data set.
|
data3.partition.column |
Optional Argument.
Specifies Partition By columns for "data3".
Values to this argument can be provided as a vector, if multiple
columns are used for partition.
Types: character OR vector of Strings (character)
|
data3.order.column |
Optional Argument. Required if "data3" is specified.
Specifies Order By columns for "data3".
Values to this argument can be provided as a vector, if multiple
columns are used for ordering.
Types: character OR vector of Strings (character)
|