Cant read count(*) value in temporary table - sql

Question

I want to fill a temporary table with values from another table and a count value, but it always throws the error:
Column name or number of supplied values does not match table
definition
My code looks like this:
CREATE TABLE #TempTable
([ObjectId] uniqueidentifier, [ListName] nvarchar(255), [HowMany] int)
INSERT INTO #TempTable
SELECT [ObjectId]
,[ListName]
,(SELECT COUNT(*) FROM [ATable] as a WHERE [ObjectId] = a.FK_ObjectId ) AS [HowMany]
FROM [AnotherTable]
It works fine for the other columns but not for the [HowMany] column.
I already tried to cast the SELECT count(*) to an integer but that also did not work.
What am I doing wrong?

Answer 1

I'm checking your request, I think that query below will help you, take a look please, I didn't use a temp table but is just the update the table names to be able to use a temp table.
As you didn't show us the structure of your table, I also made an example to make it simpler to understand, I think :-).
DECLARE #Category as table (
id int,
category nvarchar(50)
);
DECLARE #Product as table (
id int,
idCategory int,
productName nvarchar(50)
);
INSERT INTO #Category
VALUES
(1, 'Category 1'),
(2, 'Category 2'),
(3, 'Category 3')
INSERT INTO #Product
VALUES
(1,1, 'Product 1'),
(2,1, 'Product 2'),
(3,1, 'Product 3'),
(4,2, 'Product 4'),
(5,2, 'Product 5'),
(6,2, 'Product 6'),
(7,2, 'Product 7'),
(8,2, 'Product 8'),
(9,3, 'Product 9'),
(10,3, 'Product 10'),
(11,3, 'Product 11'),
(12,3, 'Product 12')
--To know how many product is used by category
SELECT * FROM
(
SELECT
C.*,
(Count(P.id) over (partition by C.ID order by C.category)) as HowManyProductByCategory
FROM
#Category as C
INNER JOIN #Product as P ON C.id = P.idCategory
) as T
GROUP BY T.id, T.category, T.HowManyProductByCategory
The result
id category HowManyProductByCategory
1 Category 1 3
2 Category 2 5
3 Category 3 4
Best Regards