Skip to content

Add Missing Solution to Self Join Section #1

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
columk1 wants to merge 2 commits into
base: master
Choose a base branch
from
Open

Add Missing Solution to Self Join Section #1

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
75129d4
Add missing solution
columk1 Jul 22, 2024
d4b5444
Update README.md
columk1 Jul 22, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 16 additions & 0 deletions README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -874,3 +874,19 @@ WHERE S1.name = 'Craiglockhart'
AND R1.num = R2.num
AND R2.stop = S2.id;
```
10. Find the routes involving two buses that can go from Craiglockhart to Lochend.
Show the bus no. and company for the first bus, the name of the stop for the transfer,
and the bus no. and company for the second bus.
```sql
SELECT R1.num, R1.company, S2.name, R4.num, R4.company
FROM route R1
JOIN route R2 ON (R1.company = R2.company AND R1.num = R2.num)
JOIN route R3 ON (R2.stop = R3.stop)
JOIN route R4 ON (R3.company = R4.company AND R3.num = R4.num)
JOIN stops S1 ON R1.stop = S1.id
JOIN stops S2 ON R2.stop = S2.id
JOIN stops S3 ON R3.stop = S3.id
JOIN stops S4 ON R4.stop = S4.id
WHERE S1.name = 'Craiglockhart' AND S4.name = 'Lochend'
ORDER BY R1.num, S2.name, R4.num
```
15 changes: 15 additions & 0 deletions solutions.sql
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -764,3 +764,18 @@ WHERE S1.name = 'Craiglockhart'
AND R1.company = R2.company
AND R1.num = R2.num
AND R2.stop = S2.id;

-- 10. Find the routes involving two buses that can go from Craiglockhart to Lochend.
-- Show the bus no. and company for the first bus, the name of the stop for the transfer,
-- and the bus no. and company for the second bus.
SELECT R1.num, R1.company, S2.name, R4.num, R4.company
FROM route R1
JOIN route R2 ON (R1.company = R2.company AND R1.num = R2.num)
JOIN route R3 ON (R2.stop = R3.stop)
JOIN route R4 ON (R3.company = R4.company AND R3.num = R4.num)
JOIN stops S1 ON R1.stop = S1.id
JOIN stops S2 ON R2.stop = S2.id
JOIN stops S3 ON R3.stop = S3.id
JOIN stops S4 ON R4.stop = S4.id
WHERE S1.name = 'Craiglockhart' AND S4.name = 'Lochend'
ORDER BY R1.num, S2.name, R4.num