Question

Could you please help me out in building a Query. I Have a table as below

Id            Info_Id                 Type
1              2                              2
2              6                              2
3              5                              3
4              8                              3
5              2                              3
6              2                              2
7              5                              2
8              8                              2
9              5                              2
10             8                              2
11             8                              2
12             5                              3
13             6                              3
14             8                              3

a query need to be framed so as to group by “Info_Id”.

I need output as below for eg:

Info_Id CountOfRec       Type2    Type3
2              3         2              1
5              4         2              2
6              2         1              1
8              5         3              2

I Tried as below but I m not able to get the efficient output

select  Info_Id, count(Id)as CountOfRec,
(select count(Id)from tbl_TypeInfo where Info_Id = 5 AND Type = 2) as Type2,
(select count(Id)from tbl_ TypeInfo where Info_Id = 5 AND Type = 3) as Type3
 from tbl_TypeInfo
where Info_Id = 5
group by Info_Id

output was this ,

Info_Id CountOfRec       Type2    Type3
5              4                              2              2

(I have to loop for each “Info_id” to get desired OP, there is thousand of records and its time consuming)

I wanted to get the highlighted output from the table. The query I have framed is not efficient and there would be good solution for this can you help me out.

Answer 1

You can use the CASE expression to only count the rows for a specific type:

SELECT Info_Id,
    COUNT(*) AS CountOfRec,
    COUNT(CASE WHEN Type = 2 THEN 1 ELSE NULL END) AS Type2
    COUNT(CASE WHEN Type = 3 THEN 1 ELSE NULL END) AS Type3
FROM tbl_TypeInfo
GROUP BY Info_Id

Add a WHERE Info_Id = 5 to retrieve results for a specific ID only.

Update: as per comments, if you do not store a table of ID’s, You need to change your IN(..) list to a virtual “table”:

SELECT vt.id,
    COUNT(*) AS CountOfRec,
    COUNT(CASE WHEN Type = 2 THEN 1 ELSE NULL END) AS Type2,
    COUNT(CASE WHEN Type = 3 THEN 1 ELSE NULL END) AS Type3
FROM (
    SELECT 1 id
    UNION SELECT 2
    UNION SELECT 3
    UNION SELECT 5
    UNION SELECT 8 
  ) AS vt LEFT JOIN tbl_TypeInfo ON vt.id = tbl_TypeInfo.Info_Id
GROUP BY vt.id