计算SQL中的组

Question

I need to create a query that counts over a GROUP BY clause. Specifically, over the Order_ID and SUB_ID columns and counts the number of Product_IDs per Order_ID and SUB_ID .

It should look like this:

However, the data is set up a little on the odd side and the only way to get the information (minus the Count column of course) is with:

SELECT
    tbl1.Order_Id
    ,tbl1.Sub_Id
    ,tbl1.Product_Id
    ,tbl1.Product_Value
    ,tbl2.Product_Owner
    ,tbl2.Owner_Id

FROM
tbl1 AS tbl1
LEFT OUTER JOIN
    tbl2 AS tbl2 ON tbl1.Order_Id=tbl2.Order_Id AND tbl1.Sub_Id=tbl2.Sub_Id

How would I add such a column?

Answer 1

I think you just need GROUP BY :

SELECT tbl1.Order_Id, tbl1.Sub_Id,
       COUNT(tbl1.Product_Id)
FROM tbl1 LEFT OUTER JOIN
     tbl2
     ON tbl1.Order_Id = tbl2.Order_Id AND tbl1.Sub_Id = tbl2.Sub_Id
GROUP BY tbl1.Order_Id, tbl1.Sub_Id;

Because the query is returning rows only from tbl1 and using a LEFT JOIN , you should be able to do:

SELECT tbl1.Order_Id, tbl1.Sub_Id,
       COUNT(tbl1.Product_Id)
FROM tbl1 
GROUP BY tbl1.Order_Id, tbl1.Sub_Id;

EDIT:

I see, that is sample data. In that case, you probably just want row_number() :

SELECT tbl1.Order_Id, tbl1.Sub_Id, tbl1.Product_Id, tbl1.Product_Value,
       tbl2.Product_Owner, tbl2.Owner_Id
       ROW_NUMBER() OVER (PARTITION BY tbl1.Order_Id, tbl1.Sub_Id ORDER BY tbl1.Product_Id) as seqnum
FROM tbl1 LEFT OUTER JOIN
     tbl2 
     ON tbl1.Order_Id = tbl2.Order_Id AND
        tbl1.Sub_Id = tbl2.Sub_Id;