Question

We currently got 100 staging tables which are loaded everyday.

I’m struggling to write a query – which give me sort PIVOT result – showing number of records inserted into staging tables by Day.

Name of tables             Day 1    Day 2   Day 3 Day 4 Day 5
--------------------------------------------------------------
AAAAA                       100     50       30    60   90

Regards

Answer 1

You need a few different steps.

DATEDIFF(DAY, <timestamp>, getDate()) will get you the number of days ago for a record.

Using CASE inside a SUM, you can then do something like…

SELECT
  'AAAA'                                                                      AS TableName,
  SUM(CASE WHEN DATEDIFF(DAY, <timestamp>, getDate()) = 1 THEN 1 ELSE 0 END)  AS Day1,
  SUM(CASE WHEN DATEDIFF(DAY, <timestamp>, getDate()) = 2 THEN 1 ELSE 0 END)  AS Day2,
  SUM(CASE WHEN DATEDIFF(DAY, <timestamp>, getDate()) = 3 THEN 1 ELSE 0 END)  AS Day3,
  SUM(CASE WHEN DATEDIFF(DAY, <timestamp>, getDate()) = 4 THEN 1 ELSE 0 END)  AS Day4,
  etc, etc
FROM
  AAAA

UNION ALL

SELECT
  'BBBB'                                                                      AS TableName,
  SUM(CASE WHEN DATEDIFF(DAY, <timestamp>, getDate()) = 1 THEN 1 ELSE 0 END)  AS Day1,
  SUM(CASE WHEN DATEDIFF(DAY, <timestamp>, getDate()) = 2 THEN 1 ELSE 0 END)  AS Day2,
  SUM(CASE WHEN DATEDIFF(DAY, <timestamp>, getDate()) = 3 THEN 1 ELSE 0 END)  AS Day3,
  SUM(CASE WHEN DATEDIFF(DAY, <timestamp>, getDate()) = 4 THEN 1 ELSE 0 END)  AS Day4,
  etc, etc
FROM
  BBBB

UNION ALL

etc, etc

That does require the code repeating itself for every table you are querying. But I think you’re stuck doing that in one way or another no matter what.

An alternative would be to put a trigger on each table, and as data is inserted/deleted, update a tracking table with the new details. That involves writing 100 triggers instead of 100 unions.

Without writing Dynamic SQL, I’m not aware of any other fundamentally different ways of doing this to aboid writing a snippet of code 100 times…