Examples: Function Processing with Default Values for Variables - Analytics Database - Teradata Vantage

SQL Data Manipulation Language

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Analytics Database
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2024-04-05
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lifecycle
latest
Product Category
Teradata Vantage™

The function mapping definition usr_AllPairsShortestPath for the function AllPairsShortestPath includes a concatenated expression for the variable TargetKey and default values for EdgeWeight and Distance.

CREATE FUNCTION MAPPING usr_AllPairsShortestPath
FOR AllPairsShortestPath SERVER TD_SERVER_DB.coprocessor
USING
vertices(vertex) IN TABLE ,
edges(edge) IN TABLE ,
sources(source) IN TABLE ,
targets(trgt) IN TABLE ,
TargetKey(GroupColumn||'_'||Distance) ,
EdgeWeight('calls') ,
MaxDistance(Distance) , Distance(1),
Directed ,GroupSize ,SequenceInputBy;

The SELECT statement specifies a value for the variable GroupColumn.

SELECT * FROM usr_AllPairsShortestPath (
ON callers AS vertices PARTITION BY callerid
ON calls AS edges PARTITION BY callerfrom
USING
GroupColumn('tabl')
) as dt ORDER BY source, target;

Upon submittal, the query is rewritten as follows. TargetKey is included because the mapping definition provides a default value for Distance and the query provides a value for GroupColumn to resolve the concatenated variable expression.

Per the mapping definition, MaxDistance is substituted for Distance. EdgeWeight is included because the mapping definition provides a default value.

SELECT * FROM AllPairsShortestPath (
ON callers AS vertices PARTITION BY callerid
ON calls AS edges PARTITION BY callerfrom
USING
TargetKey('tabl_1')
MaxDistance('1')
EdgeWeight('calls')
) as dt ORDER BY source, target;