APEX 18.1
I have a text area (right) that is populated using a DA set value action from an autocomplete item (left) (NOTE: there are 4.5 million record ids to choose from!)

I want to return records for the chosen case id's in an IG. I have a computation that generates the following list from the values in the text area using the SQL Expression
replace(replace(replace (:P1000_SEARCH_CASE_MULTIPLE,chr(10),','),chr(13),''),' ','')
and put it into the field P1004_CAS_UID_MULTIPLE

I want to pass this list into an "IN" statement in the IG where clause.
e.g.
.... I have tried the following but they don't work
where cas_uid in (:P1004_CAS_UID_MULTIPLE)
where cas_uid in (&P1004_CAS_UID_MULTIPLE.)
I couldn't get this code to work either
https://blogs.oracle.com/aramamoo/how-to-split-comma-separated-string-and-pass-to-in-clause-of-select-statement
This works but is REALLLLY slow especially if you use any LOVs in the IG
...
where instr(:P1004_CAS_UID_MULTIPLE,CAS_UID) >0
If I hard code where cas_uid in (2642884,2642886,2642888) , the performance is fast.
Any suggestions appreciated
PaulP