How to QueryOver using correlated subqueries over an aggregate value?
I have the following domain mappings:
Person
------
int PersonId
IList<PersonDetails> Details;
PersonDetails
-------------
Person Owner (mapped by using the FK field, PersonId)
string Name
string Address
DateTime UpdateDate
translated to a similiar table structure:
Person
------
PersonId (int)
Birthday (date)
PersonDetails
-------------
PersonId (FK, integer)
Name (string)
Address (string)
UpdateDate (date)
How do i recreate 开发者_JAVA百科the following SQL query using QueryOver?
SELECT *
FROM Person p INNER JOIN Details d ON p.PersonId = d.PersonId
WHERE d.UpdateDate = (SELECT MAX(UpdateDate)
FROM PersonDetails
WHERE PersonId = p.PersonId);
i.e, select the latest PersonDetails for each Person. I've seen examples, but neither of them related to a correlated subquery using an aggregae value...
Thanks, Harel
Hey, after sweating hard to find a solution, the following did the trick:
QueryOver.Of<Person>(() => personAlias)
.Left.JoinAlias(p => p.Details, () => personDetailsAlias)
.WithSubquery.WhereProperty(() => personDetailsAlias.UpdateDate).Eq(
QueryOver.Of<PersonDetails>(() => maxPersonDetailsAlias)
.Where(ps => maxPersonDetailsAlias.Owner.Id == personAlias.Id)
.Select(Projections.Max<PersonDetails>(ps => ps.UpdateDate)))
.SelectList(resList => resList.Select(() => personAlias.Id).Select(() => personDetailsAlias.Id));
so the way for joining the correlated sub-query is by using an alias the 'outer' query.
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