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

Teradata Vantage™ - SQL External Routine Programming

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1147-171K
Language
English (United States)

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;