Table Join

Databases
1

Hi!

I have Table ‘user’:
id = 1, name = John
id = 2, name = Peter
id = 3, name = Adam

Table ‘usertofolder’:
fkuserid = 1, fkfolderid = 3

Table ‘folder’:
id= 2, foldername = ‘folderB’
id = 3, foldername = ‘folderA’

I want to have a select statement to list all the names in table ‘user’ and the name for folder.id = 3.

Eg:
John, folderA
Peter, null
Adam, null

Is that possible?

Thanks.

2

Yes. Use a LEFT JOIN

3

Hi!

I have tried

SELECT * FROM user
LEFT JOIN usertouser ON user.id = fkuserid
LEFT JOIN folder ON fkfolderid = folder.id
WHERE folder.id = 3

but it only gives me one name.

4

Putting that condition on the folder table in the WHERE clause, makes the LEFT JOIN behave as an INNER JOIN.
Put it in the ON clause instead:

SELECT * FROM user
LEFT JOIN usertouser
ON user.id = fkuserid
LEFT JOIN folder
ON fkfolderid = folder.id
AND folder.id = 3

5

thanks a million