Empty result when calculating erro rate ratio

Question

I need to compare the error rate of two different HTTP client versions with that of a legacy client, for each possibile combination of status code and client version.

As an example of what I'm trying to achieve, consider that I have the following results for the legacy client:

legacy HTTP response status	% of responses with that status
401	0.02
503	0.01

and the following results for v1:

v1 HTTP response status	% of responses with that status
401	0.01
503	0.04

then I want a query that would give me the following results:

status	v1 / legacy error rate ratio
401	0.5
503	4

So, I want the query to show me that the error rate for v1 when you consider the 503 status code is 4x what I have for legacy.

I have a metric http_response that has the following labels:

• status: the HTTP response status code
• version: the HTTP client version (whose values can be legacy, v1 or v2)

I came up with the following query, but I get a "Empty query result" response when I try to run it through Thanos:

sum(rate(http_response{status="[45]..", version=~"v2|v1"}[15m])) by (version, status) /  on(version) 
group_left
sum(rate(http_response{version=~"v2|v1"}[15m])) by (version) / on (status) 

group_left

sum(rate(http_response{status=~"[45]..", version="legacy"}[15m])) by (version, status) /  on(version) 
group_left
sum(rate(http_response{version="legacy"}[15m])) by (version)

Am I missing something?

Thanks in advance!

EDIT:

Each query that calculates the error rate for each client individually does return, for example:

sum(rate(http_response{status="[45]..", version=~"v2|v1"}[15m])) by (version, status) /  on(version) 
group_left
sum(rate(http_response{version=~"v2|v1"}[15m])) by (version) / on (status) 

gives me:

result	value
{status="503", version="v1"}	0.018
{status="503", version="v2"}	0.033
{status="400", version="v1"}	0.002

while the one that determines the ratio for the legacy client gives me:

result	value
{status="503", version="legacy"}	0.016
{status="400", version="legacy"}	0
{status="500", version="legacy"}	0.001

But I can't manage to make the original query work. I wonder if this 0 in the 400 status code line would be a problem.