Thanks for your response @Kevin Chan 
 

Thanks @Benjamin De Boe 

I believe we are on a high enough version which should cater for this.

w $zv

Cache for UNIX (Red Hat Enterprise Linux for x86-64) 2017.2.2 (Build 865U) Mon Jun 25 2018 10:50:02 EDT

Hi Rupert, 

I hope you are well and enjoying robotics. 

Thanks for coming back to me.

Your recommended approach, though hugely appreciated, won't work for me I'm afraid. 

In answer to your questions:

• I am making my call from object script, as part of an already built component within a financial cache application that explicitly uses a SELECT statement
• Changing this component to use CALL instead of a SELECT is not possible due to dependencies and legacy code.

Essentially question I am asking is why some stored procedures can only be called via CALL and why can some be called by both CALL and SELECT (such as in the case of class queries)?

I get a feeling this has something to do with SQL-Invokable-Routine (SIR) - see @Dan Pasco comment here but there is almost nothing in the documentation or any code for me to go further on.

It seems that views in cache need to start with a "SELECT ..." therefore to get around this, I did the following which works: 

Class DC.NewClass1 [ ClassType = view, ViewQuery = {
SELECT '', As A, '' As B WHERE 1=2

UNION

SELECT A,B FROM DC.ClosedFuturesProc(65257,65286) --'2019-09-01','2019-09-30'
} ]
{ Parameter READONLY = 1; }