Example: Window Aggregate Function with Parameter Style SQL - Advanced SQL Engine - Teradata Database

SQL External Routine Programming

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Published
July 2021
Language
English (United States)
Last Update
2021-07-27
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B035-1147
lifecycle
previous
Product Category
Teradata Vantage™

This example declares an aggregate function that uses parameter style SQL:

/*****  C source file name: STD_DEV.c  *****/
   
#define SQL_TEXT Latin_Text
#include <sqltypes_td.h>
#include <string.h>
#include <math.h>

void STD_DEV ( FNC_Phase     phase,
               FNC_Context_t *fctx,
               FLOAT         *x,
               FLOAT         *result,
               int           *x_i,
               int           *result_i,
               char          sqlstate[6],
               SQL_TEXT      *function_name,
               SQL_TEXT      *specific_name,
               SQL_TEXT      error_message[257])
{
     ...
}

The corresponding CREATE FUNCTION statement looks like this:

CREATE FUNCTION STD_DEV(x FLOAT)
RETURNS FLOAT
CLASS AGGREGATE
LANGUAGE C
NO SQL
PARAMETER STYLE SQL
EXTERNAL;