I have two table, users and comments.
In the users table, there're columns id and username.
In the comments table I have user_id and his message.
And I wanted to create a table that select the username and his comment count when I search a particular username.
How do I write this?
my testing attempt:
SELECT COUNT(*) AS comment_count
FROM song_comments
RIGHT JOIN users
WHERE user_id = 7 AND comments.user_id = users.id
Try this:
SELECT U.Username, COUNT(SC.message) AS comment_count
FROM song_comments SC JOIN
users U ON U.id=SC.user_id
WHERE U.user_id = 7
GROUP BY U.Username
This gives you users and count
select u.username, count(c.user_id) as comment_count
from users u
join comments c on u.id = c.user_id
group by u.username
You can add a where to get one user's count
select u.username, count(c.user_id) as comment_count
from users u
join comments c on u.id = c.user_id
where u.username = 'Hogan'
group by u.username
Related
I have three tables.
users, friends and communityusers tables.
I am trying to build a facebook like group system. User will try to search his/her friends from friend lists to add them to the group.
So here I am trying to remove those friends who are already added in the group. Here group users table is communityusers..
This is the structure of my communityusers table.
id | community_id | user_id
I am not being able to use this table with my current query.
SELECT f.id, u.id as user_id, u.userName, u.firstName, u.lastName, u.profilePic from friends f, users u
WHERE CASE
WHEN f.following_id=1
THEN f.follower_id = u.id
WHEN f.follower_id=1
THEN f.following_id = u.id
END
AND
f.status= 2
AND
(
u.firstName LIKE 's%' OR u.lastName LIKE 's%'
)
This query returns the friends lists of user id 1 now I want exclude users filtering from the communityusers table.
user_id from this query shouldn't be present in the communityusers table. How can I filter this from communityusers or third table?
Please let me know if question is not clear.
Any suggestion, idea and help would be highly appreciated.
Thank you so much.
Edit
After running the query I get
My communityusers table
See user_id = 2 is also selected from the above query. I want to remove the user_id = 2 from the result since it exists in the communityusers table.
I am trying to create a Fiddle but for some reason it's not working for me.
Thank you again.
#sadek
Simply use not in, in where condition
SELECT f.id, u.id as user_id, u.userName, u.firstName, u.lastName, u.profilePic
from friends f inner join users u on
CASE WHEN f.following_id=1 THEN f.follower_id = u.id WHEN f.follower_id=1 THEN f.following_id = u.id
END AND f.status= 2
where u.id not in (select distinct user_id from communityusers) and (u.firstName LIKE 's%' OR u.lastName LIKE 's%')
Try using left join with communityuser table by given condition cu.user_id is null - this will give you those users which are not in communituuser table
select a.* from
(SELECT f.id, u.id as user_id, u.userName, u.firstName, u.lastName, u.profilePic from friends f inner join users u
on CASE WHEN f.following_id=1 THEN f.follower_id = u.id WHEN f.follower_id=1 THEN f.following_id = u.id
END AND f.status= 2 where u.firstName LIKE 's%' OR u.lastName LIKE 's%')a
left join (select * from communityuser where community_id<>4) cu on a.user_id=cu.user_id
where cu.user_id is null
I have two tables, one with settingIDs and values of those settings for each userID and another with userIDs, their emails and user names.
I am trying to join the values of specific settings, the problem is that not all users have this specific setting tied to their ID, so I end up with less rows than I actually need.
Table 1
userID settingID settingValue
Table 2
userID userDOB userEmail userName
My query looks like this:
SELECT u.userID, u.userEmail, s.settingValue
FROM users u
LEFT JOIN userSettings s ON u.userID = s.userID
WHERE s.settingID = 1
What do I need to do to get all of the users in the list?
Your where clause turns you left join into an inner join. Put the condition in the JOIN
SELECT u.userID, u.userEmail, s.settingValue
FROM users u
LEFT JOIN userSettings s ON u.userID = s.userID
AND s.settingID = 1
you can use UNION ALL clause to combine two JOINS
SELECT u.userID, u.userEmail, s.settingValue
FROM users u
LEFT userSettings s
ON u.userID = s.userID
UNION ALL
SELECT u.userID, u.userEmail, s.settingValue
FROM users u
RIGHT userSettings s
ON u.userID = s.userID
I have 2 tables:
posts: userid, lastuserid
users: id, name
I need to join posts.userid = users.id and posts.lastuserid = users.id to get username and lastusername.
My query did as below:
SELECT posts. * , users.name, vUsers.name
FROM posts
INNER JOIN users ON users.id = posts.userid
INNER JOIN Users ON vUsers.id = posts.lastuserid
Is there any other (better) way to do this?
Your query is probably correct. I would encourage you to use table aliases that are abbreviations for the things you are looking for:
SELECT p. * , u.name as username, l.name as lastusername
FROM posts p INNER JOIN
users u
ON u.id = p.userid INNER JOIN
users l
ON l.id = p.lastuserid;
Your query has something called vUsers, which is not defined.
I have 2 tables in my database. Table users and table profile.
users(user_id, surname, email)
profile(profile_id, country, user_id)
user_id in table profile, is FK (comes from users table). I have the following query in order to select all surnames "smith" from my database, that are from country "USA". This is my query:
SELECT u.name,
u.surname,
u.email,
u.user_id,
p.user_id
FROM users u
INNER JOIN profile p ON p.country = 'USA'
WHERE u.surname = 'smith' AND u.user_id = p.user_id
this query works fine, but the problem is that returns only 1 result and not all results from my database (people with surname smith that are from USA). Any idea where it might be the wrong and how to correct it?
You should put the u.user_id = p.user_id condition with ON condition because you want to apply JOIN on 'user_id' field. And where clause should have the remaining condition.
SELECT u.name,
u.surname,
u.email,
u.user_id,
p.user_id
FROM users u
INNER JOIN profile p ON u.user_id = p.user_id
WHERE u.surname = 'smith' And p.country = 'USA'
You can read about INNER JOINS
Use only the columns in your join on condition that are relevant for the join. The columns that link 2 tables together. And put the rest in the where clause. That should work:
SELECT u.name,
u.surname,
u.email,
u.user_id,
p.user_id
FROM users u
INNER JOIN profile p ON u.user_id = p.user_id
WHERE p.country = 'USA'
AND u.surname = 'smith'
This is also better for readability. You can read it like this:
SELECT these columns from table users. JOIN also table profile ON this 2 columns. After that filter the data and return only the records WHERE these conditions are met.
I have a payments table that has the following structure.
**Payments**
id
name
created_by - user_id
closed_by - user_id
**Users**
user_id
name
surname
What is the best way to show both the name and surname of the user who has created and closed the payment file.
The only way i can think this could work would be using a subquery for both(created_by,closed_by fields) thanks
Try this:
SELECT p.id, p.name,
CONCAT (u1.name,' ', u1.surname) created,
CONCAT (u2.name,' ', u2.surname) closed,
FROM payments p INNER JOIN users u1
ON p.created_by = u1.user_id
INNER JOIN users u2
ON p.closed_by = u2.user_id
EDITED: if you want name and surname splitted
SELECT p.id, p.name,
u1.name created_name, u1.surname created_surname,
u2.name closed_name, u2.surname closed_surname,
FROM payments p INNER JOIN users u1
ON p.created_by = u1.user_id
INNER JOIN users u2
ON p.closed_by = u2.user_id
A strict join is not enough, I think you can use joins in the where clause
select name, surname
from
payments p, users u
where
u.user_id = p.created_by
and u.user_id = p.closed_by
You can join to a single table multiple times, but you have to use an alias.
select
p.*,cr.*,cl.*
from
payments p
join users cr
on p.created_by = cr.user_id
join users cl
on p.closed_by = cl.user_id