Question

I have a table that looks like this:

Customer ID, MDN, Plan, StartDate, EndDate, Term, SMS Usage, Voice Usage

Ordering by SMS Usage in ascending or descending order

I want to delete the top 5% of all records, and the bottom 50% leaving behind the remaining 90% of customers

Answer 1

;WITH x AS
(
    SELECT CustomerID FROM 
    (
      SELECT TOP 5 PERCENT CustomerID FROM dbo.table 
      ORDER BY [SMS Usage]
    ) AS lowest
    UNION ALL
    SELECT CustomerID FROM
    (
      SELECT TOP 5 PERCENT CustomerID FROM dbo.table
      ORDER BY [SMS Usage] DESC
    ) AS highest
)
-- DELETE t FROM dbo.table AS t INNER JOIN x ON t.CustomerID = x.CustomerID;
SELECT CustomerID FROM t;

When you are happy that the query is returning the right rows, you can uncomment the DELETE and comment or remove the last line.