The Wise Owl logo (an owl and the company name)

Our training courses
AI - Articial Intelligence Azure C# Excel Microsoft 365 MySQL Power Apps Power Automate Power BI and DAX Python Report Builder SQL SQL Server VBA Macros

Other training resources
Tips and tricks Guides and tutorials Blogs Exercises YouTube tutorials YouTube shorts Test your skills Consultancy Courseware Self-paced courses Newsletters Publications

Our training venues
London Manchester Across the UK At your site Online

Why we are different
Hundreds of published reviews Small class sizes Outstanding courseware Online classroom (Almost) no cancellations Wise Owl trainers only Genuine integrity Invoices after training 30+ years of Wise Owl Our top 100 clients

Details for svjmandryk

svjmandryk has participated in the following threads:

Added by svjmandryk on 01 Aug 2020 at 17:04

Spoiler alert :)

********************************

my solution:

create function [dbo].[getAuthorId](@authorName varchar(max))
returns varchar(max)
as 

begin
    return 
        (select DoctorId 
            from tblDoctor 
            where lower(DoctorName) like '%' + @authorName)
end
go

create function [dbo].[getEpisodesByAuthor](@authorName varchar(max))
returns table
as 

    return select e.EpisodeId, e.Title, e.DoctorId, ee.EnemyId, ee.EpisodeEnemyId
    from tblEpisode as e
    left join tblEpisodeEnemy as ee
        on e.EpisodeId = ee.EpisodeId
    where DoctorId = [dbo].getAuthorId(@authorName)

go

 

create function [dbo].[getEpisodesNotByAuthor](@authorName varchar(max))
returns table
as 
    return select e.EpisodeId, e.Title, e.DoctorId, ee.EnemyId, ee.EpisodeEnemyId
    from tblEpisode as e
    join tblEpisodeEnemy as ee
        on e.EpisodeId = ee.EpisodeId
    where DoctorId <> [dbo].getAuthorId(@authorName)     

go

create function [dbo].[getIdsOfEpisodeWithoutExclusiveEnemies](@authorName varchar(max))
returns table
as 

    return
        select distinct EpisodeId 
        from tblEpisodeEnemy
        where EnemyId in (
            select distinct EnemyId 
            from [dbo].[getEpisodesNotByAuthor](@authorName))

go

declare @authorName varchar(max) = 'Tennant'

select distinct EpisodeId, Title, DoctorId --, EnemyId, EpisodeEnemyId
from [dbo].[getEpisodesByAuthor](@authorName)
where 
    EpisodeId not in (
        select EpisodeId 
        from [dbo].getIdsOfEpisodeWithoutExclusiveEnemies(@authorName)) 
order by Title


PS This was the trickiest one for me :)

Head office

Kingsmoor House

Railway Street

GLOSSOP

SK13 2AA

London

Landmark Offices

99 Bishopsgate

LONDON

EC2M 3XD

Manchester

Holiday Inn

25 Aytoun Street

MANCHESTER

M1 3AE
Google reviews star logo

© Wise Owl Business Solutions Ltd 2025. All Rights Reserved.

End of small page here
Please be aware that our website uses cookies!
I'm OK with this Tell me more ...