Sort data in SQL using Dynamic SQL in SAP HANA

In order to execute dynamic SQL in your stored procedure, you need to use the EXECUTE IMMEDIATE statement. This statement allows you to build and execute SQL queries dynamically at runtime, which is particularly useful when you need to sort data based on variables or user input.

Basic Dynamic SQL Syntax

You can use SQL as shown below to execute dynamic sorting ?

EXECUTE IMMEDIATE 'SELECT <COLUMN NAMEs> FROM <TABLE NAME> ORDER BY ' || :<ORDERING COLUMN> || ' DESC';

Complete Example

Here's a complete example showing how to implement dynamic sorting in a SAP HANA stored procedure ?

CREATE PROCEDURE dynamic_sort_example(
    IN sort_column NVARCHAR(50),
    IN sort_direction NVARCHAR(10)
)
LANGUAGE SQLSCRIPT
AS
BEGIN
    DECLARE dynamic_query NVARCHAR(500);
    
    dynamic_query := 'SELECT employee_id, employee_name, salary 
                      FROM employees 
                      ORDER BY ' || :sort_column || ' ' || :sort_direction;
    
    EXECUTE IMMEDIATE :dynamic_query;
END;

Important Limitations

Another thing to notice is that if you are planning to use the table type in the final select statement with dynamic SQL, it will not work. Dynamic SQL does not support table type in select statements.

What you can try as a workaround is that you can dump the data in a temporary table before using it in the dynamic SQL and then use a temporary variable in the SQL statement. This approach ensures compatibility with dynamic SQL execution while maintaining the flexibility of runtime query construction.

Conclusion

Dynamic SQL with EXECUTE IMMEDIATE provides flexibility for runtime sorting in SAP HANA, though it requires careful handling of table types through temporary tables when needed.