Consider the following function definition:
CREATE FUNCTION ascii (string_expr TD_ANYTYPE) RETURNS TD_ANYTYPE LANGUAGE C NO SQL SPECIFIC ascii EXTERNAL NAME 'CS!ascii!UDFs/ascii.c' PARAMETER STYLE SQL;
This function returns the ASCII numeric value of the first character of the input string. It accepts input strings with the following data types:
- CHARACTER
- VARCHAR
- CLOB
- UDT with a CHARACTER, VARCHAR, or CLOB attribute.
- ARRAY with an element type of CHARACTER or VARCHAR.
The function accepts the character set associated with the input string. If no character set is explicitly specified, the default character set is used.
The return type supported by this function is BYTEINT, SMALLINT, or INTEGER. To specify the desired return type for the function, use the RETURNS data type or RETURNS STYLE column expression clause when invoking the function.
The following is a sample query that invokes this function:
SELECT (ascii('hello') RETURNS INTEGER);
The output returned by the query is:
ascii('hello')
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104
For more details about this function, including the corresponding C code example for the function, see Teradata Vantage™ - SQL External Routine Programming, B035-1147.