Question

I am trying to do a search using QueryOver however the results returned, although are right based on the search criteria, are being duplicated.

Here is the code I am using to count the results, which works correctly

// disjunction to find query string in note text of tag list
var disjunction = new Disjunction();
disjunction.Add(Restrictions.On<Note>(e => e.Text).IsInsensitiveLike(query));

var tagSubQuery = QueryOver.Of<Note>().JoinQueryOver(x => x.Tags).Where(x => x.Text.IsInsensitiveLike(query)).Select(x => x.Id);
disjunction.Add(Subqueries.WhereProperty<Note>(x => x.Id).In(tagSubQuery));

// find notes between dates and based on disjunction
var notes = this.DataOver.Where(x => x.CreatedUTC >= startDate && x.CreatedUTC <= endDate).Where(disjunction);

// only show notes within permitted accounts
var subnotes = QueryOver.Of<Note>().JoinQueryOver(x => x.Accounts).Where(x => x.Company.Id == user.Company.Id).Select(x => x.Id);
var returned = notes.WithSubquery.WhereProperty(x => x.Id).In(subnotes);

return returned.RowCount();

If I change the last line to a select statement with skip and take like so

return returned.OrderBy(x => x.CreatedUTC).Desc.Skip(skip).Take(take).List<Note>();

Then I get the 3 notes back, instead of 2. 1 note is duplicated, while the other is ok. I can only assume that is because the query matched two of the tags linked to one note.

The SQL outputted by nHibernate profiler is as follows

SELECT TOP (20 /* @p0 */) this_.Id           as Id47_1_,
                 this_.CreatedGMT   as CreatedGMT47_1_,
                 this_.CreatedLocal as CreatedL3_47_1_,
                 this_.CreatedUTC   as CreatedUTC47_1_,
                 this_.UpdatedGMT   as UpdatedGMT47_1_,
                 this_.UpdatedLocal as UpdatedL6_47_1_,
                 this_.UpdatedUTC   as UpdatedUTC47_1_,
                 this_.CreatedBy    as CreatedBy47_1_,
                 this_.UpdatedBy    as UpdatedBy47_1_,
                 this_.Text         as Text47_1_,
                 this_.UserId       as UserId47_1_,
                 this_.Suppress     as Suppress47_1_,
                 tags2_.NoteId      as NoteId3_,
                 tag3_.Id           as TagId3_,
                 tag3_.Id           as Id27_0_,
                 tag3_.CreatedGMT   as CreatedGMT27_0_,
                 tag3_.CreatedLocal as CreatedL3_27_0_,
                 tag3_.CreatedUTC   as CreatedUTC27_0_,
                 tag3_.UpdatedGMT   as UpdatedGMT27_0_,
                 tag3_.UpdatedLocal as UpdatedL6_27_0_,
                 tag3_.UpdatedUTC   as UpdatedUTC27_0_,
                 tag3_.CreatedBy    as CreatedBy27_0_,
                 tag3_.UpdatedBy    as UpdatedBy27_0_,
                 tag3_.Text         as Text27_0_
FROM   [dev.Client].[dbo].Note this_
       left outer join [dev.Client].[dbo].TagToNote tags2_
         on this_.Id = tags2_.NoteId
       left outer join [dev.Client].[dbo].Tag tag3_
         on tags2_.TagId = tag3_.Id
WHERE  this_.Id in (SELECT this_0_.Id as y0_
                    FROM   [dev.Client].[dbo].Note this_0_
                           inner join [dev.Client].[dbo].NoteToAccount accounts3_
                             on this_0_.Id = accounts3_.NoteId
                           inner join [dev.Client].[dbo].Account account1_
                             on accounts3_.ClientAccountId = account1_.Id
                    WHERE  this_0_.Id in (SELECT this_0_0_.Id as y0_
                                          FROM   [dev.Client].[dbo].Note this_0_0_
                                          WHERE  (this_0_0_.CreatedUTC >= '2012-06-01T00:00:00.00' /* @p1 */
                                                  and this_0_0_.CreatedUTC <= '2012-06-30T00:00:00.00' /* @p2 */)
                                                 and (lower(this_0_0_.Text) like '%dtes%' /* @p3 */
                                                       or this_0_0_.Id in (SELECT this_0_0_0_.Id as y0_
                                                                           FROM   [dev.Client].[dbo].Note this_0_0_0_
                                                                                  inner join [dev.Client].[dbo].TagToNote tags3_
                                                                                    on this_0_0_0_.Id = tags3_.NoteId
                                                                                  inner join [dev.Client].[dbo].Tag tag1_
                                                                                    on tags3_.TagId = tag1_.Id
                                                                           WHERE  lower(tag1_.Text) like '%dtes%' /* @p4 */)))
                           and account1_.CompanyId = 1 /* @p5 */)
ORDER  BY this_.CreatedUTC desc

If I put this directly into SQL management studio it returns 3 results, two of which are the same.

Answer 1

That’s because of the left join, which causes a cartesian product. You should apply the DistinctRootTransformer by appending this:

.TransformUsing(Transformers.DistinctRootEntity)