A couple of Haskell/SQL examples.

person.hs

-- Both of these functions do the same thing: return some that, if given a DB connection, will return a list of records.

-- No type-checking, but obvious equivalence to SQL.
getPerson :: UUID -> SqlPersistM [Entity Person]
getPerson uuid = rawSql
  rawSql "SELECT ?? FROM person WHERE person_id = ?" [uuid]

-- More DSL-ish, but more compile-time guarantees.
getPerson2 :: UUID -> SqlPersistM [Entity Person]
getPerson2 uuid =
  select $
  from $
  \person -> where_ (person ^. PersonPersonId ==. val uuid) return person