Question

I have multiple databases all containing the same structure but not the same content, A001, A002, A003, A004….A020 what is the quickest way to reformulate the query in a short & convenient way so that I can get the table output as follows:

Code | Desc | A001 | A002 | A003 | A004 
=====+======+======+======+======+=======
ABCD | ABCD |  0   |   1  |   3  |  4

The query is as follows for A001

SELECT AC1.cCode, SUM(AC1.cQtyin) - SUM(AC1.cQtyout) AS A001, AB1.cDes
FROM
A001.dbo.pmStock AC1 
INNER JOIN
A001.dbo.pmProduct AB1 ON AC1.Id = AB1.Prid
GROUP BY AC1.cCode, AB1.cDes

Its a bit confusing on how to do the grouping, and if theres a convenient way to loop around or something to I dont have to reiterate for each A001 to A020. Is this possible in SQL? Particularly using multiple databases (A001 and A002…. are all different databases on the same server)

Answer 1

I’m on my iPhone, so this is a bit of a headache to type. But, the following may be at least a little maintainable. It may be worth making the sub query into a view.

SELECT
  Product.cDes,
  Stock.cCode,
  SUM(CASE WHEN Stock.source = 'A001' THEN Stock.amount ELSE 0 END) AS A001,
  SUM(CASE WHEN Stock.source = 'A002' THEN Stock.amount ELSE 0 END) AS A002,
  SUM(CASE WHEN Stock.source = 'A003' THEN Stock.amount ELSE 0 END) AS A003,
  Etc, Etc
FROM
  A001.dbo.Product
INNER JOIN
(
  SELECT 'A001' AS source, id, cCode, cQtyIn - cQtyOut AS amount FROM A001.dbo.pmStock
  UNION ALL
  SELECT 'A002' AS source, id, cCode, cQtyIn - cQtyOut AS amount FROM A002.dbo.pmStock
  UNION ALL
  SELECT 'A003' AS source, id, cCode, cQtyIn - cQtyOut AS amount FROM A003.dbo.pmStock
  UNION ALL
  Etc, etc
)
  AS Stock
    ON Stock.Id = Product.Prid
GROUP BY
  Stock.cCode,
  Product.cDes