How to get columns with specific string - sql

Question

I am working in SQL Server 2014 and below is my database with which I am working on and need some analysis done on it.
Upon inspecting the database sample carefully we can notice a number 8777 in L9 and in L13 column.
Now I want to get only those columns which have 8777 in them and in the end a column named "count" which shows how many times the number appeared means I need in output something like this as shown below:
So far I have written this query which is giving the category and subcategory correct. But it is showing all the columns. I have no idea how to count the occurrences of a number and show its count in a count column.
select *
from Sheet2$
where '8777' IN ([L1],[L2],[L3],[L4],[L5],[L6],[L7],[L8],[L9],[L10],[L11],[L12],[L13]

Answer 1

To dynamically limit the columns, you would need Dynamic SQL
Example
Select *
Into #Temp
From YourTable A
Unpivot ( Value for Item in ([L1], [L2],[ L3], [L4], [L5], [L6], [L7], [L8], [L9], [L10], [L11], [L12], [L13]) ) u
Where Value = 8777
Declare #SQL varchar(max) = Stuff((Select Distinct ',' + QuoteName(Item) From #Temp Order by 1 For XML Path('')),1,1,'')
Select #SQL = '
Select *,[Count] = sum(1) over()
From #Temp A
Pivot (max(Value) For [Item] in (' + #SQL + ') ) p'
Exec(#SQL);
Returns
Category SubCategory L13 L9 Count
C1 SC1 NULL 8777 2
C1 SC3 8777 NULL 2

Answer 2

Hmmm. I think you want the original rows with the count. I think this is:
declare #cols nvarchar(max);
declare #sql nvarchar(max);
set #cols = (select distinct ', ' + v.colname
from t cross apply
(values ('l1', l1),
('l2', l2),
('l3', l3),
('l4', l4),
('l5', l5),
('l6', l6),
('l7', l7),
('l8', l8),
('l9', l9),
('l10', l10),
('l11', l11),
('l12', l12),
('l13', l13)
) v(colname, val)
where v.val = '8777'
for xml path ('')
);
set #sql = '
select category, subcategory' + #cols + ',
count(*) over () as cnt
from t
';
exec sp_executesql #sql;
The only difference from your result is that the count is on every row. That can easily be adjusted using a case expression, but I'm not sure it is necessary.
If you want the count in only one row, then:
set #sql = '
select category, subcategory' + #cols + ',
(case when row_number() over (order by category, subcategory) = 1
then count(*) over ()
end) as cnt
from t
order by category, subcategory
';

Answer 3

You can try this part as a replacement of John's answer's second query to get the proper count, it does not achieve the exact thing you want but can be a work around.
Declare #sql varchar(max) = Stuff((Select Distinct ',' + QuoteName(Item)
From #Temp Order by 1 For XML Path('')),1,1,'')
print #sql;
Select #SQL = '
Select *,value=8777
From #Temp A
Pivot (Count(Value) For [Item] in (' + #sql + ') ) p'
print #sql;
Exec(#SQL);
I just used count function in pivot in place of sum.