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

Here is an example of how to declare a scalar function that uses parameter style SQL:

/*****  C source file name: substr.c  *****/
   
#define  SQL_TEXT Latin_Text
#include <sqltypes_td.h>
#include <string.h>
   
void udf_scalar_substr( VARCHAR_LATIN *inputString,
                        INTEGER       *start,
                        VARCHAR_LATIN *result,
                        int           *inputStringIsNull,
                        int           *startIsNull,
                        int           *resultIsNull,
                        char          sqlstate[6],
                        SQL_TEXT      extname[129],
                        SQL_TEXT      specific_name[129],
                        SQL_TEXT      error_message[257] )
{
     ...
}

For a complete example of the scalar function, see Example: Basic Scalar Function.

The corresponding CREATE FUNCTION statement looks like this:

CREATE FUNCTION udfSubStr
  (strexp  VARCHAR(512),
   n1  INTEGER)
RETURNS VARCHAR(512)
LANGUAGE C
NO SQL
EXTERNAL NAME 'CS!substr!udfsrc/substr.c!F!udf_scalar_substr'
PARAMETER STYLE SQL;