Number of output columns to be returned by the function is not known before it is invoked, so limit them to a maximum of maximum_output_columns columns.
The upper limit is 2,048 columns per table function.
There is no default value.
Example: Dynamic Result Row Specification
The following example defines a table function named extract_store_data that has variable output columns.
The SELECT request following the function definition uses extract_store_data to parse the input text string and extract store sales data into the store_data table.
CREATE FUNCTION extract_store_data (
text VARCHAR(32000),
from_store INTEGER)
RETURNS TABLE VARYING COLUMNS (10)
SPECIFIC extract_store_data
LANGUAGE C
NO SQL
PARAMETER STYLE SQL
NOT DETERMINISTIC
EXTERNAL NAME 'SS!extract_store_data!extract_store_data.c';
INSERT INTO store_data
SELECT *
FROM (TABLE(extract_store_data('…', 1000)
RETURNS store_data) AS store_sales;