I have two tables Users and User_Org.
Users ( user_id,first name,last name, active_ind, email)
User_Org (user_id, org_id)
I have to write a Oracle SQL query, where it should return all users whose active_ind is 1 and org_id of associated user in User_org match the given org_id.
I have tried below, it is not working
select *
from Users u
join User_ORG org
where org.ORGANIZATION_ID = 12345
and Active_ind != 0;
You are missing the on clause of the join. Other than that, if you want users with an active_ind of 1, I'd state that directly with an equality check (=) instead of dancing around it with an inequality check.
SELECT u.*
FROM users u
JOIN user_org org ON u.user_id = org.user_id
WHERE org.org_id = 12345 AND active_ind = 1
Related
I have 3 tables user, student_data, teacher_data. A user can be either student or a teacher. If it is the teacher I want to join user and teacher_data. And if it is a student then I want to join user with student_data.
How I can do this join with the condition.
I'd combine the two data tables in a sub-query, and then join the users to that.
SELECT
*
FROM
usr u
LEFT JOIN
(
SELECT user_id, datum, xxx, NULL AS yyy FROM student_data
UNION ALL
SELECT user_id, datum, NULL, yyy FROM teacher_data
)
d
ON d.user_id = u.id
https://dbfiddle.uk/?rdbms=oracle_21&fiddle=9b801ea739d42fe50c00ef4e17eaf143
NOTES:
The columns selected from the two data tables must match
Any unmatched columns must either be skipped or filled with NULL
Please don't call a table user, it's a reserved keyword and Oracle won't allow it.
You can write it like this:
select u.user_id,
s.student_id,
t.teacher_id
from usr u
left join student_data s on u.user_id=s.student_id
left join teacher_data t on u.user_id=t.teacher_id
where s.student_id is not null or t.teacher_id is not null
order by u.user_id
For every user_id check if he is a student or teacher, if he is student get his student column values else null, if he is a teacher get his teacher column values else null.
maybe try a union - something like this
select user_id, user_other_stuff
from user, student_data
where user.user_id = student_data.user_id
UNION
select user_id, user_other_stuff
from user, teacher_data
where user.user_id = teacher_data.user_id
User
USER_ID USERNAME
1 -
2 Chris
3 Dave
4 Vlad
Issue
Creator RESOLVER VERIFIER
2 3 4
2 3 1
3 1 1
expected output:
Creator RESOLVER VERIFIER
Chris Dave Vlad
Chris Dave -
Dave - -
current code I have:
SELECT creatorid.username, resolverid.username, verifierid.username
FROM issue
JOIN user creatorid ON issue.creator = creatorid.user_id
JOIN user resolverid ON issue.resolver = resolverid.user_id
JOIN user verifierid ON issue.verifier = verifierid.user_id
do i have to join the table 3 times to get the corresponding username of the user_id in issue table or is there is a simpler way of doing this? Asking as this is a simplified version of the tables, the User and Issue table contains a lot of other columns. Thanks
Because of the join, you will see each issue three times which is not what you want. You could use three scalar subqueries to get around that:
select i.id,
(select username from users u1 where u1.user_id = i.creator) as creator,
(select username from users u2 where u2.user_id = i.resolver) as resolver,
(select username from users u3 where u3.user_id = i.verifier) as verifier
from issue i;
This isn't going to be fast though.
Another option is to aggregate all user_id / username pairs into a JSON object, then use that in a sub-query:
select i.id, -- other columns from the issue table
u.names ->> i.creator::text as creator,
u.names ->> i.resolver::text as resolver,
u.names ->> i.verifier::text as verifier
from issue i
join lateral (
select jsonb_object_agg(user_id, username) as names
from users u
where u.user_id in (i.creator, i.resolver, i.verifier)
) u on true;
The traditional way to do this is:
select i.*, uc.username, ur.username, uv.username
from issue i left join
users uc
on uc.user_id = i.creator left join
users ur
on ur.user_id = i.resolver left join
users uv
on uv.user_id = i.verifier;
I got 3 tables, Users, courses and course realation tables. I want to get users who aren't on specific course. So I figure I need somehow merge 2 selects with right join. How could I make one select from 2 selects?
SELECT ID, NAME, LASTNAME, ROLE FROM COURSERELATION JOIN USERS ON
ID_USER = ID WHERE ID_COURSE = ?
RIGTH JOIN
SELECT ID, NAME, LASTNAME, ROLE from COURSERELATION JOIN USERS ON
ID_USER = ID WHERE ID_COURSE != ?
You need to extract users for which it doesn't exist a record of that user for the specific course. You can filter the rows using a NOT EXISTS clause over a subquery.
Please try below query:
SELECT u.ID,
u.NAME,
u.LASTNAME,
u.ROLE
FROM USERS u
WHERE NOT EXISTS (SELECT 1
FROM COURSERELATION s
WHERE s.id_user = u.id
AND s.id_course = 'YOUR_COURSE_ID_HERE' )
I have two tables (Users and Pairs). The Pairs table contains 3 columns, an ID and then a user1ID and user2ID.
Users
ID firstName surname
------------------------------
1043 john doe
2056 jane doe
Pairs
ID user1ID user2ID
------------------------------
1 1043 2056
I'm then looking at using a select statement to get the user details base on the ID of the Pairs table:
SELECT users1.*, users2.*
FROM Pairs
JOIN Users users1 ON Pairs.user1ID = users1.IDNumber
JOIN Users users2 ON Pairs.user2ID = users2.IDNumber
WHERE Pairs.ID = 1
Which returns the right details for the two users, however they're all on one row, how can I get it to return each user on a separate row as they are in the Users table?
SELECT users1.*, users2.*
FROM Pairs
JOIN Users
ON Pairs.user1ID = users.IDNumber
OR Pairs.user2ID = users.IDNumber
WHERE Pairs.ID = 1
Just use an OR statement in your ON condition instead of 2 joins.
IN will work also.
SELECT *
FROM Pairs p
JOIN Users u ON u.ID IN (p.user1ID, p.User2ID)
WHERE p.ID = 1
I have two tables:
Users: ID, first_name, last_name
Networks: user_id, friend_id, status
I want to select all values from the users table but I want to display the status of specific user (say with id=2) while keeping the other ones as NULL. For instance:
If I have users:
? first_name last_name
------------------------
1 John Smith
2 Tom Summers
3 Amy Wilson
And in networks:
user_id friend_id status
------------------------------
2 1 friends
I want to do search for John Smith for all other users so I want to get:
id first_name last_name status
------------------------------------
2 Tom Summers friends
3 Amy Wilson NULL
I tried doing LEFT JOIN and then WHERE statement but it didn't work because it excluded the rows that have relations with other users but not this user.
I can do this using UNION statement but I was wondering if it's at all possible to do it without UNION.
You need to put your condition into the ON clause of the LEFT JOIN.
Select
u.first_name,
u.last_name,
n.status
From users u
Left Join networks n On ( ( n.user_id = 1 And n.friend_id = u.id )
Or ( n.friend_id = 1 And n.user_id = u.id )
Where u.id <> 1
This should return you all users (except for John Smith) and status friend if John Smith is either friend of this user, or this user is friend of John Smith.
You probably don't need a WHERE clause, and instead of that, put the condition into the "ON" clause that follows your "LEFT JOIN". That should fix your issues. Also, make sure that the main table is on the left side of the left join, otherwise, you should use a right join.
In addition to the (correct) replies above that such conditions should go in the ON clause, if you really want to put them in the WHERE clause for some reason, just add a condition that the value can be null.
WHERE (networks.friendid = 2 OR networks.friendid IS NULL)
From what you've described, it should be a case of joining a subset of networks to users.
select id, first_name, last_name, status
from users u
left join networks n on u.id = n.user_id
and n.friend_id = 1
where id <> 1;
The left join will keep rows from users that do not have a matching row in networks and adding the and n.friend_id = 1 limits when the 'friends' status is returned. Lastly, you may choose to exclude the row from users that you are running the query for.