Question

I need help with SQL (MSSQL), where I am sorting by multiple boolean types in order to group the results, but also need to sort by a date field within each of the type groupings.

The following SQL seemingly works ok:

Select * from staff ORDER BY admin DESC, hr DESC, sales DESC, it DESC, updated DESC

The trick is that some records have more than 1 type selected and then the output gets messed up. I only need to show staff in one grouping, but they should appear sorted by updated DESC within each grouping.

This is the output I get:

Name  updated    admin  hr     sales  it   
-------------------------------------------
fred  2012/04/01 true   true
bill  2011/10/01 true   true
joe   2012/04/01 true
sam   2012/03/01 true
jo    2012/02/01 true
beth  2012/03/01        true
mary  2012/02/01        true
harry 2011/02/01               true  true
gary  2012/04/01               true
bruce 2012/04/01                     true

This is the output I need

Name  updated    admin  hr     sales  it   
-------------------------------------------
fred  2012/04/01 true   true
joe   2012/04/01 true
sam   2012/03/01 true
jo    2012/02/01 true
bill  2011/10/01 true   true
beth  2012/03/01        true
mary  2012/02/01        true
gary  2012/04/01               true
harry 2011/02/01               true  true
bruce 2012/04/01                     true

Hope that makes sense.

Answer 1

You can use case expressions in the order by clause for conditional sorting.

SELECT *
FROM staff
ORDER BY
    admin DESC,
    CASE admin WHEN 'true' THEN updated END DESC,
    hr DESC,
    CASE hr WHEN 'true' THEN updated END DESC,
    sales DESC,
    CASE sales WHEN 'true' THEN updated END DESC,
    it DESC,
    updated DESC