Cannot perform an aggregate function on an expression containing an aggregate or a subquery sql server 2012 - sql

Question

I am performing a query and its showing an error Cannot perform an aggregate function on an expression containing an aggregate or a subquery.
the query is
SELECT
tbl_Product.ID,
tbl_Product.ArticleID,
tbl_Product.Title,
tbl_Product.Description,
tbl_Product.Price,
tbl_ProductType.Name,
tbl_Status.StatusName,
tbl_VisibilityStatus.VisibilityStatus,
MAX(
CASE
WHEN tbl_RelatedProduct.TypeOfRelation = 1 THEN 'Bundle'
WHEN tbl_Product.ID IN
(
select tbl_RelatedProduct.Product2ID
from tbl_RelatedProduct
where tbl_RelatedProduct.Product1ID=9 and tbl_RelatedProduct.TypeOfRelation=1) THEN 'Bundle'
END
) 'Bundle',
MAX(
CASE
WHEN tbl_RelatedProduct.TypeOfRelation = 2 THEN 'Follower' END) 'Follower',
MAX(
CASE
WHEN tbl_RelatedProduct.TypeOfRelation = 3 THEN 'Related' END) 'Related'
FROM
tbl_Product inner JOIN
tbl_ProductType ON tbl_Product.ProductTypeId = tbl_ProductType.ID Inner JOIN
tbl_Status ON tbl_Product.StatusID = tbl_Status.ID Inner JOIN
tbl_VisibilityStatus ON tbl_Product.VisibilityID = tbl_VisibilityStatus.ID
left JOIN tbl_RelatedProduct ON tbl_Product.ID = tbl_RelatedProduct.Product1ID
group by
tbl_Product.ID,
tbl_Product.ArticleID,
tbl_Product.Title,
tbl_Product.Description,
tbl_Product.Price,
tbl_ProductType.Name,
tbl_Status.StatusName,
tbl_VisibilityStatus.VisibilityStatus
order by tbl_Product.Title
ANyone know how to help on this...plsss

Answer 1

The below line is causing an issue:
WHEN tbl_Product.ID IN
(
select tbl_RelatedProduct.Product2ID
from tbl_RelatedProduct
where tbl_RelatedProduct.Product1ID=9 and tbl_RelatedProduct.TypeOfRelation=1) THEN 'Bundle'
END
) 'Bundle',
You are using MAX with CASE and one of the statements within CASE uses a subquery, which is causing the error. You might want to consider using joins instead of subqueries to implement this.

Answer 2

SELECT tbl_Product.ID,tbl_Product.ArticleID,tbl_Product.Title,tbl_Product.Description,tbl_Product.Price,tbl_ProductType.Name,tbl_Status.StatusName, tbl_VisibilityStatus.VisibilityStatus,
Case when ((select count(1) from tbl_RelatedProduct where tbl_RelatedProduct.TypeOfRelation = 1 and tbl_RelatedProduct.Product1ID = tbl_Product.Id) > 0) then 1
when ((select count(1) from tbl_RelatedProduct where tbl_RelatedProduct.TypeOfRelation = 1 and tbl_RelatedProduct.Product2ID = tbl_Product.Id) > 0) then 1
else 0 end as Bundle,
(select count(1) from tbl_RelatedProduct where tbl_RelatedProduct.TypeOfRelation = 2 and tbl_RelatedProduct.Product1ID = tbl_Product.Id) as Follower,
(select count(1) from tbl_RelatedProduct where tbl_RelatedProduct.TypeOfRelation = 3 and tbl_RelatedProduct.Product1ID = tbl_Product.Id) as Related
FROM tbl_Product
inner JOIN
tbl_ProductType ON tbl_Product.ProductTypeId = tbl_ProductType.ID Inner JOIN
tbl_Status ON tbl_Product.StatusID = tbl_Status.ID
Inner JOIN
tbl_VisibilityStatus ON tbl_Product.VisibilityID = tbl_VisibilityStatus.ID
Its resolved with this query :)

Answer 3

I think I see what you are trying to do, and it is a bit strange. I would output this all as a single column, and lose the MAX aggregate as follows:
SELECT
p.ID,
p.ArticleID,
p.Title,
p.Description,
p.Price,
pt.Name,
s.StatusName,
v.VisibilityStatus,
CASE
WHEN rp.TypeOfRelation = 1 OR (rp2.Product1ID = 9 AND rp2.TypeOfRelation = 1)
THEN 'Bundle'
WHEN rp.TypeOfRelation = 2
THEN 'Follower'
WHEN rp.TypeOfRelation = 3
THEN 'Related'
ELSE Null
END AS Relation
FROM
tbl_Product p
INNER JOIN tbl_ProductType pt
ON p.ProductTypeId = pt.ID
INNER JOIN tbl_Status s
ON p.StatusID = s.ID
INNER JOIN tbl_VisibilityStatus v
ON p.VisibilityID = v.ID
LEFT JOIN tbl_RelatedProduct rp
ON p.ID = rp.Product1ID
LEFT JOIN tbl_RelatedProduct rp2
ON p.ID = rp2.Product2ID
ORDER BY p.Title
If you would still like to have them in separate columns, just break up the CASE statement as follows:
SELECT
p.ID,
p.ArticleID,
p.Title,
p.Description,
p.Price,
pt.Name,
s.StatusName,
v.VisibilityStatus,
CASE
WHEN rp.TypeOfRelation = 1 OR (rp2.Product1ID = 9 AND rp2.TypeOfRelation = 1)
THEN 'Bundle'
ELSE Null
END AS Bundle,
CASE
WHEN rp.TypeOfRelation = 2
THEN 'Follower'
ELSE Null
END AS Follower,
CASE
WHEN rp.TypeOfRelation = 3
THEN 'Related'
ELSE Null
END AS Related
FROM
tbl_Product p
INNER JOIN tbl_ProductType pt
ON p.ProductTypeId = pt.ID
INNER JOIN tbl_Status s
ON p.StatusID = s.ID
INNER JOIN tbl_VisibilityStatus v
ON p.VisibilityID = v.ID
LEFT JOIN tbl_RelatedProduct rp
ON p.ID = rp.Product1ID
LEFT JOIN tbl_RelatedProduct rp2
ON p.ID = rp2.Product2ID
ORDER BY p.Title