This page has 8 threads | Add post

Exercises

Finding our exercises useful? Please consider helping us to share more!

Software ==>	SQL (203 exercises)
Topic ==>	More exotic joins (5 exercises)
Level ==>	Average difficulty
Subject ==>	SQL training

Write an SQL outer join to show unmatched records in another table

This exercise is provided to allow potential course delegates to choose the correct Wise Owl Microsoft training course, and may not be reproduced in whole or in part in any format without the prior written consent of Wise Owl.

Before you can do this exercise, you'll need to download and unzip this file .

If you haven't already done so, run the script in the above folder to generate the Doctor Who database.

The database contains details of companions, and the episodes each appeared in:

Each companion can appear in one or more episodes.

Use this to list the names of the companions who haven't featured in any episodes. You should find there's one of them, but we won't spoil the surprise by saying who it is!

Create a query based on the companions table, with an outer join to the episode companion table.

Save this query as outre.sql (that's neither a misspelling nor a funny joke), and close it down.

You can unzip this file to see the answers to this exercise, although please remember this is for your personal use only.

You can find other training resources for the subject of this exercise here:

This page has 8 threads

Add a new post

From:	Bhavya59
When:	01 Aug 24 at 09:10

SELECT [CompanionName]

,EpisodeId

FROM tblCompanion c LEFT OUTER JOIN tblEpisodeCompanion ec

ON c.CompanionId=ec.CompanionId

WHERE EpisodeId IS NULL

From:	Devender
When:	16 Jan 24 at 09:32

/*Use this to list the names of the companions who haven't

featured in any episodes. You should find there's one of them,

but we won't spoil the surprise by saying who it is!

use DoctorWho

select cn.companionname --et.episodetype

from

tblCompanion cn full outer join tblEpisodeCompanion ci

on cn.CompanionId= ci.CompanionId

full outer join tblEpisode et

on et.EpisodeId=ci.EpisodeId

where episodetype is null

From:	Rupchand
When:	11 Jan 24 at 09:18

select CompanionName,

COUNT(episodeid)

from tblCompanion

left join tblepisodecompanion

on tblCompanion.CompanionId = tblepisodecompanion.CompanionId

group by CompanionName having COUNT(episodeid)<1

Result: Sarah jane smith

From:	Aravindh_sql
When:	27 May 22 at 09:33

SELECT
tblCompanion.CompanionName AS Companion,
tblEpisode.EpisodeType
FROM tblCompanion
LEFT JOIN
tblEpisodeCompanion
ON
tblCompanion.CompanionId = tblEpisodeCompanion.CompanionId
LEFT JOIN
tblEpisode
ON
tblEpisodeCompanion.EpisodeId = tblEpisode.EpisodeId
WHERE tblEpisode.EpisodeType IS NULL

ANSWER

-- Companion= Sarah Jane Smith

From:	FloridaMan
When:	26 Sep 21 at 01:28

select *

from

[dbo].[tblEpisode] e

left join [dbo].[tblEpisodeCompanion] ec

on e.EpisodeId = ec.EpisodeId

--where e.EpisodeId is null

full outer join [dbo].[tblCompanion] c

on ec.CompanionId = c.CompanionId

From:	waltz
When:	09 May 21 at 11:23

SELECT cm.[CompanionId],[CompanionName]
FROM [dbo].[tblCompanion] AS cm left outer JOIN [dbo].[tblEpisodeCompanion] AS Ec
ON cm.CompanionId = Ec.CompanionId
except
(SELECT cm.[CompanionId],[CompanionName]
FROM [dbo].[tblCompanion] AS cm inner JOIN [dbo].[tblEpisodeCompanion] AS Ec
ON cm.CompanionId = Ec.CompanionId);
GO

From:	walteragwe
When:	20 Jan 21 at 03:43

From:	grao
When:	07 Nov 17 at 01:34

I am not getting any results. Is this the right code?

use doctorwho

Select companionname
from tblCompanion as c
left outer join tblEpisodeCompanion as e
on c.CompanionId=e.EpisodeCompanionId
where e.EpisodeCompanionId =null

From:	DbEnthusiast
When:	19 Dec 20 at 16:11

SELECT C.CompanionName,C.WhoPlayed,EC.*
FROM [dbo].[tblCompanion] C
LEFT JOIN [dbo].[tblEpisodeCompanion] EC ON C.CompanionId = EC.CompanionId
WHERE EC.EpisodeCompanionId IS NULL OR EC.CompanionId IS NULL

From:	Phithel
When:	18 Oct 18 at 18:57

USE DoctorWho

SELECT
   C.[CompanionName],
   E.[Title]
FROM
   [dbo].[tblCompanion] AS C
       LEFT OUTER JOIN [dbo].[tblEpisodeCompanion] AS EC
           ON C.CompanionId = EC.CompanionId
       LEFT OUTER JOIN [dbo].[tblEpisode] AS E
           ON EC.EpisodeId = E.EpisodeId
WHERE
   E.Title IS NULL

I got Sarah Jane Smith

From:	linjom
When:	19 Apr 18 at 07:21

select c.CompanionName,c.WhoPlayed,E.Episodeid,E.EpisodeCompanionId
from tblCompanion as C
   left join tblEpisodeCompanion as E
   on c.CompanionId = E.CompanionId
   where (E.EpisodeCompanionId is null or E.EpisodeId is null)

Result i got Sarah Jane Smith Elisabeth Sladen NULL NULL

From:	Zerish
When:	16 May 18 at 07:33

Right join will do just fine

SELECT [CompanionName]
FROM [dbo].[tblEpisodeCompanion]
RIGHT JOIN [dbo].[tblCompanion]
ON tblEpisodeCompanion.CompanionId=tblCompanion.CompanionId
WHERE EpisodeCompanionId IS NULL

From:	Sevid
When:	23 Mar 18 at 00:50

You must use "where e.CompanionId is null", this is the result that I got :

CompanionName CompanionId WhoPlayed
Sarah Jane Smith 8 Elisabeth Sladen

Add a new post

EXERCISE TOPIC

SQL EXERCISES

SQL EXERCISES

Write an SQL outer join to show unmatched records in another table

Head office

London

Manchester