How to create where statement based on result of multiset - kotlin

Question

So, i would like to filter my query by exact match in result of multiset. Any ideas how to do it in JOOQ?
Example:
val result = dsl.select(
PLANT_PROTECTION_REGISTRATION.ID,
PLANT_PROTECTION_REGISTRATION.REGISTRATION_NUMBER,
PLANT_PROTECTION_REGISTRATION.PLANT_PROTECTION_ID,
multiset(
select(
PLANT_PROTECTION_APPLICATION.ORGANISM_ID,
PLANT_PROTECTION_APPLICATION.ORGANISM_TEXT
).from(PLANT_PROTECTION_APPLICATION)
.where(PLANT_PROTECTION_APPLICATION.REGISTRATION_ID.eq(PLANT_PROTECTION_REGISTRATION.ID))
).`as`("organisms")
).from(PLANT_PROTECTION_REGISTRATION)
// here i would like to filter my result only for records that their organisms contain specific
// organism id
.where("organisms.organism_id".contains(organismId))

Answer 1

I've explained the following answer more in depth in this blog post
About the MULTISET value constructor
The MULTISET value constructor operator is so powerful, we'd like to use it everywhere :) But the way it works is that it creates a correlated subquery, which produces a nested data structure, which is hard to further process in the same SQL statement. It's not impossible. You could create a derived table and then unnest the MULTISET again, but that would probably be quite unwieldy. I've shown an example using native PostgreSQL in that blog post
Alternative using MULTISET_AGG
If you're not nesting things much more deeply, how about using the lesser known and lesser hyped MULTISET_AGG alternative, instead? In your particular case, you could do:
// Using aliases to make things a bit more readable
val ppa = PLANT_PROTECTION_APPLICATION.as("ppa");
// Also, implicit join helps keep things more simple
val ppr = ppa.plantProtectionRegistration().as("ppr");
dsl.select(
ppr.ID,
ppr.REGISTRATION_NUMBER,
ppr.PLANT_PROTECTION_ID,
multisetAgg(ppa.ORGANISM_ID, ppa.ORGANISM_TEXT).`as`("organisms"))
.from(ppa)
.groupBy(
ppr.ID,
ppr.REGISTRATION_NUMBER,
ppr.PLANT_PROTECTION_ID)
// Retain only those groups which contain the desired ORGANISM_ID
.having(
boolOr(trueCondition())
.filterWhere(ppa.ORGANISM_ID.eq(organismId)))
.fetch()