I'm trying to select all users that their user id is not in another table.
Users table (user id is user_id)
Ghosts table (user id is id)
this is what I got so far:
$sql = "select * from users where users.user_id <> ghosts.id;";
Please advise...
Cheers!
You can use NOT IN:
select * from users u where u.user_id not in (select id from ghosts);
or NOT EXISTS:
select *
from users u
where not exists (select 1 from ghosts g where g.id = u.user_id)
Something like this may also work, although I like Brian's answer.
SELECT *
FROM users u
LEFT JOIN ghosts g
ON u.user_id = g.id
WHERE g.id IS NULL
Related
I am working on social networking site.
I've three tables one is user table which is used to store user details, another table is follow table which is used for followers following list.
In this table I am storing user_id and follower_id.
Third table is user_friends in this I'm storing user_id and friend_userid.
I want to search the user from my friends list and follow list. For this i've written query like this:-
select f.follower_id,uf.friend_userid,u.user_id,u.first_name,u.last_name from tbl_user u
LEFT JOIN tbl_userfriends uf ON uf.friend_userid = u.user_id
LEFT JOIN tbl_follow f ON f.follower_id = u.user_id
where uf.friend_userid != '11'
AND u.first_name LIKE '%a%'
This query returning users only who are friends it is not returning the follow users.
Any help will be appreciated. Thanks in Advance.
You're joining tbl_follow on the Follower ID being equal to the User ID. I suspect that's probably not right.
If you don't already have one you'll need a user id key in the follower table to join on, then you can change your join to;
LEFT JOIN tbl_follow f ON f.userid = u.user_id
i've done this by using following query:-
select u.user_id,u.first_name,u.last_name from tbl_user u LEFT JOIN tbl_userfriends uf ON uf.friend_userid = u.user_id LEFT JOIN tbl_follow f1 ON f1.follower_id = u.user_id LEFT JOIN tbl_follow f2 ON f2.user_id = u.user_id where (uf.user_id = '11' OR f1.user_id = '11' OR f2.follower_id = '11') AND (u.first_name LIKE '%s%' OR u.last_name LIKE '%s%') AND u.status = '0' group by u.first_name
This query returning me all the users who are my followers, friends and to whom i am following.
I have two table users and album. In users table there is user_id primary key .In other table albums there are multiple rows with that user_id because every time when a user upload a new album it uploads with user_id as foreign key. I want to select only once the user_id with other table(album) ignore other result set.
How can I achieve this?
SELECT a.*, b.*
FROM users a
INNER JOIN album b
ON a.user_ID = b.user_ID
INNER JOIN
(
SELECT user_ID, MAX(photo_id) max_rec
FROM album
GROUP BY user_ID
) c ON b.user_ID = c.user_ID AND
b.photo_id = c.max_rec
SELECT album.* FROM album LEFT JOIN users ON user.id = album.id WHERE user.id = SOMEIDHERE
I believe this will work, your not giving me a whole lot of info to work with.
SELECT *
FROM ( SELECT u.*, a.*
FROM users AS u
INNER JOIN album AS a
ON u.user_ID = a.user_ID
ORDER BY a.created DESC) AS h
GROUP BY user_ID
ORDER BY b.created DESC -> ORDER BY whatever row you wish for. In this case the newest one is chosen.
I have two tables. I want to draw a sample of the first table except where the person in the first table is also in a second table. Am having trouble doing this seemingly simple query.
table users
id|name
table catuser
id|userid|catid
I have tried
SELECT u.*,c.userid FROM `users` u
LEFT JOIN `catuser` c
ON (u.id = c.userid AND c.userid <> '197')
WHERE u.id = '1'
and variations to no avail. Would appreciate any suggestions.
How abt. this:
SELECT u.*,c.userid
FROM `users` u
LEFT JOIN `catuser` c
ON u.id = c.userid
WHERE u.id = '1'
AND c.userid <> '197'
AND c.userid is null
SELECT * FROM users WHERE id NOT IN (SELECT DISTINCT userid FROM catuser)
If you want to query only users that have one or more categories, you can use a WHERE EXISTS query:
SELECT u.* FROM `users` u
WHERE EXISTS (SELECT * FROM catuser WHERE catuser.userid = u.id)
Another possibility is to do a left join, and check whether the join succeeded on checking on null:
SELECT u.*, c.* FROM `users` u
LEFT JOIN catuser c ON u.id = c.userid
WHERE c.id IS NOT NULL
If there is no corresponding row in catuser, all catuser fields will be null. By checking whether c.id is not null, you only include the rows with a category.
Note that the join may return a user multiple time, if he is in multiple categories.
I'm struggling with this for hours so please help me.
This is my users table
id | username | last_activity(timestamp for online system)
And this is my friends table
id | uid | fid
What I want is to order the output by last_activity
My current query looks like this:
SELECT fid FROM friends WHERE uid='$user_id'
SELECT f.fid FROM f.friends
LEFT JOIN users u ON f.uid = u.id
WHERE uid=$user_id
ORDER BY u.last_activity DESC
You want to use INNER JOIN to join the two tables:
SELECT f.fid
FROM friends f
INNER JOIN users u
ON u.id = f.id
ORDER BY u.last_activity DESC
Always make sure you type out a real JOIN clause as some ways are old and getting more and more unsupported.
Read more here:
INNER JOIN on w3schools
I think you want
SELECT f.fid AS fid
FROM friends f, users u
WHERE f.uid = u.id AND f.uid = $user_id
ORDER BY u.last_activity DESC
I assume your problem is that fid is on one table, but the ordering criterion last_activity is on another table. The goal of this query is to JOIN each row in the friends table with the corresponding row in the users table (via the WHERE clause).
Assuming uid in friends table is foreign key references to id in users
table. so using INNER JOIN you can retrieve your desired results.
SELECT f.fid
FROM friends f INNER JOIN user_tb u
ON u.id = f.uid
WHERE f.uid = '$user_id'
ORDER BY u.last_activity DESC;
This question already has an answer here:
Closed 11 years ago.
Possible Duplicate:
Self referencing relation with followers|friends users
Hi there.
I have two tables called users and users_friends.
users:
id INT
username VARCHAR
.....
users_friends:
user_id INT
friend_id INT
PRIMARY KEY (`user_id`,`friend_id`)
How can I get the information about a specific users friends? Let's say I want to list friends associated with the user with an id of 5.
Can't get my joins working, everything I try ends up with no result. Any ideas? This should be I simple query with two INNER JOIN I think but can't manage.
Then a second question is how do I structure this using Kohana 3.1 ORM? Perhaps I shouldn't?
EDIT: Anyone have an idea about doing this with Kohana 3 ORM?
What about something like this :
select users.*
from users
inner join users_friends on users_friends.friend_id = users.user_id
where users_friends.user_id = 5
SELECT *
FROM `users` AS u
INNER JOIN `users_friends` AS uf ON u.id = uf.user_id
WHERE u.id = '5'
this is the query with INNER JOIN
if all of the information is stored in users you will need to join users once more
SELECT ufu.*
FROM `users` AS u
INNER JOIN `users_friends` AS uf ON u.id = uf.user_id
INNER JOIN `users` AS ufu ON uf.friend_id = ufu.user_ud
WHERE u.id = '5'
Ofcourse a JOIN is possible, but that wont be faster then a simple query like:
SELECT *
FROM users
WHERE id IN (
SELECT friendID FROM user_friends WHERE userID=5
)
But, this only lists the friends from user 5. If you want the other way around, so list the people that say user 5 is a friend, this query is also easier to alter.
SELECT *
FROM users
WHERE id IN (
SELECT userID FROM user_friends WHERE friendID=5
)
isn't it a simple:
Select friend_id from users_friends where user_id = 5
5 being the users id.
Off the top of my head:
SELECT friend_id, username
FROM users_friends JOIN users
ON users_friends.friend_id = users.id
WHERE user_id = 5;