Without testing, but I'd try something like:

PU_LAST(DOMAIN("CASE"."CASE_ID"),"CASE"."ORDER_TYPE", "CASE"."CASE_ID"="CASE"."BLOCKED_BY")

Unfortunately then it also takes the "CASE"."BLOCKED_BY" value from the child table.

PQL would need something like the keyword THIS in programming languages.

PU_LAST(DOMAIN("CASE"."CASE_ID"),"CASE"."ORDER_TYPE", "CASE"."CASE_ID"=THIS."CASE"."BLOCKED_BY")

Then it would be clear which table the column has to be taken from.

But thank you for the suggestion! :)

Do you mean that in the output you get several correct answers AND a line with the blocking case_id? in that case you could refine the filter with AND CASE.CASE_ID <> CASE.CASE_ID

But, yes, that "THIS" will help a lot... I have found that, specially with PU, PQL requires lot of "try-and-error"

try-and-error -> absolutely!

When I use a statement like your's I am getting only NULL values. That is because Celonis only looks into the child table (for both sides of the condition). So it look if a Case is blocked by itself, which is of course never true and also not what I want.

Damm... I didn't know this "that is because Celonis only looks into the child table (for both sides of the condition)"

I will dig into the documentation to see if I can imagine some "hack" to reference also the parent table in the filter