i have an api which i make calls to and i need alot of data from different tables so i use joins on them, now the problem is that whilst i have 4 replies, and 5 interactions the data always returns 20 replies and 20 interactions this is the result:
screen_name screen_state replies interactions alerts
sjerd 0 20 20 0
i use this query to count the records and results:
SELECT u.screen_name,
u.screen_state,
count(r.id) AS replies,
count(i.id) AS interactions,
count(a.alerts) AS alerts
FROM users u
LEFT JOIN reply r ON u.id = r.user
LEFT JOIN interactions i ON u.id = i.user_id
LEFT JOIN alerts a ON u.id = a.user_id WHERE u.id ='2'
GROUP BY u.id, u.screen_state
can someone see why it's returning 20 while i only have 7 rows of replies in total in reply table,
and 5 rows of interactions in total in interaction table.
each row is 1 reaction or reply.
Your counts are always going to give the same result as all tables are joined at the same level.
You need to do your counts as inline sub-queries (or whatever - I can never remember the correct terminology):
SELECT u.screen_name,
u.screen_state,
(select count(*) from reply r where u.id = r.user) AS replies,
(select count(*) from interactions i where u.id = i.user_id) AS interactions,
(select count(*) from alerts a where u.id = a.user_id) AS alerts
FROM users u
WHERE u.id ='2'
SELECT u.screen_name, u.screen_state,
count(DISTINCT r.id) AS replies,
count(DISTINCT i.id) AS interactions,
count(DISTINCT a.alerts) AS alerts
FROM users u
LEFT JOIN reply r ON u.id = r.user
LEFT JOIN interactions i ON u.id = i.user_id
LEFT JOIN alerts a ON u.id = a.user_id WHERE u.id ='2'
GROUP BY u.id, u.screen_state
Related
I have a Spring MVC blog with functionality for Post and Comment voting. I want to return the top 3 users based on number of votes they've received on all their posts and comments.
tables:
users u [id, username]
posts p [id, u.id]
comments c [id, p.id, u.id]
post_votes pv [p.id, u.id, type (1 or -1)]
comment_votes cv [c.id, u.id, type (1 or -1)]
The following statement gives me total votes per user by querying two separate voting tables and then adding the totals together:
SELECT
(SELECT SUM(type)
FROM posts_votes pv
JOIN posts p ON p.id = pv.post_id
JOIN users u ON u.id = p.user_id
WHERE u.id LIKE ?1)
+
(SELECT SUM(type)
FROM comments_votes cv
JOIN comments c ON c.id = cv.comment_id
JOIN users u ON u.id = c.user_id
WHERE u.id LIKE ?1)
That works fine with a WHERE clause per user id... But now I'm trying to find just the top 3 users that have the most votes and I'm having too much difficulty. This is what I have so far:
SELECT u.id, u.username, IFNULL(SUM(pv.type), 0) AS totalPostVotes
FROM posts_votes pv
JOIN posts p ON p.id = pv.post_id
JOIN users u ON u.id = p.user_id
GROUP BY u.id ORDER BY totalPostVotes DESC LIMIT 3
That above statement works by itself giving me: u.id, u.username, and totalPostVote in descending order. So does the one below for comments:
SELECT u.id, u.username, IFNULL(SUM(cv.type), 0) AS totalCommentVotes
FROM comment_votes cv
JOIN comments c ON c.id = cv.comment_id
JOIN users u ON u.id = c.user_id
GROUP BY u.id ORDER BY totalCommentVotes DESC LIMIT 3
Great! But I want that third column SUM result to be essentially "totalVotes" and contain the sum of both of those subqueries. Then I'll GROUP BY u.id ORDER BY totalVotes DESC LIMIT 3.
Something like this:
SELECT u.id, u.username, SUM(
(SELECT IFNULL(SUM(pv.type), 0) AS totalPostVotes
FROM posts_votes pv
JOIN posts p ON p.id = pv.post_id
JOIN users u ON u.id = p.user_id
GROUP BY u.id ORDER BY totalPostVotes DESC LIMIT 1)
+
(SELECT IFNULL(SUM(cv.type), 0) AS totalCommentVotes
FROM comments_votes cv
JOIN comments c ON c.id = cv.comment_id
JOIN users u ON u.id = c.user_id
GROUP BY u.id ORDER BY totalCommentVotes DESC LIMIT 1))
AS totalVotes from users u
GROUP BY u.id, u.username ORDER BY totalVotes DESC LIMIT 3
id | username | totalVotes
2 user2 11
1 user1 11
29 user29 11
What's happening is the result of totalVotes is indeed the correct vote count, 11, for the "top" user, but none of those users are the real top user, and the correct vote is being repeated 3 times in the guise of other users. I'm not even sure how users are being sorted at that point because they're not in an order I recognize.
The subqueries work separately (they give me the correct user) when I add SELECT "u.id, u.username " IFNULL(SUM()) but then if I run the whole block, I get the error "Operand should contain 1 column(s)" So I delete them and revert to only SELECT IFNULL(SUM())
I'm also noticing the subqueries are only allowed LIMIT 1. How would I get the top 3, then? Should I do a UNION somewhere or is "+" sufficient? This is rather confusing. Can someone please help me with this? Any help is appreciated. Thanks in advance!
Updated code, thank you Peter:
SELECT
u.username,
pv_sum.total AS postTotal,
cv_sum.total AS commentTotal,
IFNULL(pv_sum.total, 0) + IFNULL(cv_sum.total, 0) as totalVotes
FROM users u
LEFT JOIN (
SELECT p.user_id, IFNULL(SUM(pv.type), 0) AS total
FROM posts p
JOIN posts_votes pv ON pv.post_id = p.id
GROUP BY p.user_id
) pv_sum ON pv_sum.user_id = u.id
LEFT JOIN (
SELECT c.user_id, IFNULL(SUM(cv.type), 0) AS total
FROM comments c
JOIN comments_votes cv ON cv.comment_id = c.id
GROUP BY c.user_id
) cv_sum ON cv_sum.user_id = u.id
GROUP BY u.username, postTotal, commentTotal
ORDER BY totalVotes DESC LIMIT 3;
Don't place your subqueries in your SELECT-part, but join them on the users-table:
SELECT
u.username,
pv_sum.total AS postTotal,
cv_sum.total as commentTotal,
IFNULL(pv_sum.total, 0) + IFNULL(cv_sum.total, 0) as totalVotes
FROM users u
LEFT JOIN (
SELECT p.user_id, IFNULL(SUM(pv.type), 0) AS total
FROM posts p
JOIN post_votes pv ON pv.post_id = p.id
GROUP BY p.user_id
) pv_sum ON pv_sum.user_id = u.id
LEFT JOIN (
SELECT c.user_id, IFNULL(SUM(cv.type), 0) AS total
FROM comments c
JOIN comment_votes cv ON cv.comment_id = c.id
GROUP BY c.user_id
) cv_sum ON cv_sum.user_id = u.id
GROUP BY u.id
ORDER BY totalVotes DESC
LIMIT 3;
Fiddle: http://sqlfiddle.com/#!9/980cb2/11
I'm struggling a little bit with a query and hope you can help.
I have two tables. On with all the users and one with information from submitted forms.
Both contain the user ID.
What I would need to find out is which user from the users table does not appear on the report table.
This is what I have so far:
SELECT u.ID, u.display_name, u.user_email, r.user_id
FROM users AS u
LEFT JOIN report AS r ON u.ID = r.user_id
WHERE NOT EXISTS(
SELECT *
FROM report AS rr
WHERE u.ID = rr.user_id
)
This seems to be fine for the users who absolutely have never submitted the form.
But the reports table also contains a date column and I was wondering how I can get this grouped by day.
In the front end then I will hopefully have a table which shows:
date: user:
2015-01-01 user a
2015-01-01 user f
2015-01-02 user g
2015-01-02 user a
2015-01-03 user z
2015-01-03 user x
Where the users are those who have not submitted the form that day.
Hope you can help. Thank in advance!
If you want to get a list of users that doesn't have any rows in the report table then you can generate a set that is the Cartesian product of the users and the dates that are present in the report table, and then do a left join with that set and check for null.
The Cartesian set formed by the cross join will contain all possible combinations of dates and users; that is would the report table would contain is all users had added reports on all available dates.
select r.date, u.user_id
from report r
cross join users u
left join (select r.date, r.user_id from users as u join report as r on u.id = r.user_id)
a on a.date = r.date and a.user_id = u.user_id
where a.date is null
Sample SQL Fiddle
With most other databases this could have been done with a set difference operator (minus or except) instead of a left join.
I'm making assumptions about column names in your report table for this answer:
SELECT x.report_date, u.user_id, u.display_name
FROM users u
JOIN (
SELECT DISTINCT report_date
FROM reports
) x
LEFT JOIN reports r
ON r.user_id = u.user_id
AND r.report_date = x.report_date
WHERE r.report_date IS NULL
ORDER BY x.report_date, u.user_id
Check out this fiddle: http://sqlfiddle.com/#!9/407ac/5
Left outer join with where clause...
Here is a good link ...
http://blog.codinghorror.com/a-visual-explanation-of-sql-joins/
SELECT * FROM `users`
LEFT OUTER JOIN `report`
ON `users`.`ID` = `report`.`user_id`
WHERE `report`.`user_id` IS null
ORDER BY `report`.`Date`
Surely you could just pass in the date you wanted to check?
so something like this (using #reportDate as the parameter):
SELECT * FROM users
LEFT OUTER JOIN report
ON users.ID = report.user_id
WHERE report.user_id IS NULL
AND report.Date = #reportDate
You can get the pairs of users/dates without reports. Generate all possible rows using a cross join and then filter out the ones that exist:
select u.*, r.date
from users u cross join
(select distinct date from reports r) d left join
reports r
on u.id = r.user_id and d.date = r.date
where r.userid is null;
I've got 3 tables:
submissions, submissions_votes, and users. My current query:
SELECT s.*, u.username, u.avatar, SUM(sv.up) helpfulVotes
FROM submissions s
INNER JOIN users u
ON s.user_id = u.id
LEFT JOIN submissions_votes sv
ON s.id = sv.submission_id
WHERE s.id = 23
GROUP BY s.id
Will return for me the submission details, the user who submitted it, and the amount of helpfulVotes on the submission (which comes from the submissions_votes table).
This works fine, but what I'd like to do is test for a condition within the SUM(sv.up) to see if the any of the users within that sum matches a particular user_id from submissions.
I was thinking of doing something like this but it doesn't work:
SELECT s.*, u.username, u.avatar, SUM(sv.up) helpfulVotes,
SUM (IF(sv.user_id = 15, count, 1)) as currentUserVoted, <---- ???
FROM submissions s
INNER JOIN users u
ON s.user_id = u.id
LEFT JOIN submissions_votes sv
ON s.id = sv.submission_id
WHERE s.id = 23
GROUP BY s.id
How can I see if there is a match within that sum to the current user's id (in this case, 15)?
Yes you can use condition in SUM() just like SUM (sv.user_id = 15) will give you the count for user 15
SELECT
s.*,
u.username,
u.avatar,
SUM(sv.up) helpfulVotes,
SUM(sv.user_id = 15) AS currentUserVoted
FROM
submissions s
INNER JOIN users u
ON s.user_id = u.id
LEFT JOIN submissions_votes sv
ON s.id = sv.submission_id
WHERE s.id = 23
GROUP BY s.id
or if you want to sum another column based on user id you can use CASE
SUM (CASE WHEN sv.user_id = 15 THEN sum_other_col ELSE 0 END) as currentUserVoted
We have following tables...
users
id, username password email
user_clubs
id, user_id, club_name
sales
id, club_id, amount, admin_fees, dnt
We are trying to get total sum of admin_fees as outstanding for user_id(for example 5), and we tried following...
SELECT u.id, count(c.id), SUM(s.admin_fees) as total_admin_fees
FROM users u
LEFT JOIN user_clubs c ON c.user_id = u.id
LEFT JOIN sales s ON s.club_id = c.id
WHERE u.id = 5
GROUP BY u.id;
Which is only returning results for first row, which is incorrect, Please help to resolve.
here is sql fiddle to test.
thanks
Try this one for user_id = 5 there are two club ids and with amount 2,5 so total should be 7
SELECT u.id, COUNT(c.id), SUM(s.admin_fees) AS total_admin_fees
FROM users u
LEFT JOIN user_clubs c ON c.user_id = u.id
LEFT JOIN sales s ON s.club_id = c.id
WHERE u.id = 5
GROUP BY s.club_id;
for all users you can do this
SELECT u.id, COUNT(c.id), SUM(s.admin_fees) AS total_admin_fees
FROM users u
LEFT JOIN user_clubs c ON c.user_id = u.id
LEFT JOIN sales s ON s.club_id = c.id
GROUP BY u.`id`;
Fiddle
It must be pretty easy, but i can't think of any solution nor can I find an answer somewhere...
I got the table 'users'
and one table 'blogs' (user_id, blogpost)
and one table 'messages' (user_id, message)
I'd like to have the following result:
User | count(blogs) | count(messages)
Jim | 0 | 3
Tom | 2 | 3
Tim | 0 | 1
Foo | 2 | 0
So what I did is:
SELECT u.id, count(b.id), count(m.id) FROM `users` u
LEFT JOIN blogs b ON b.user_id = u.id
LEFT JOIN messages m ON m.user_id = u.id
GROUP BY u.id
It obviously doesn't work, because the second left join relates to blogs not users. Any suggestions?
First, if you only want the count value, you could do subselects:
select u.id, u.name,
(select count(b.id) from blogs where userid = u.id) as 'blogs',
(select count(m.id) from messages where userid = u.id) as 'messages'
from 'users'
Note that this is just a plain sql example, I have no mysql db here to test it right now.
On the other hand, you could do a join, but you should use an outer join to include users without blogs but with messages. That would imply that you get several users multiple times, so a group by would be helpful.
If you use an aggregate function in a select, SQL will collapse all your rows into a single row.
In order to get more than 1 row out you must use a group by clause.
Then SQL will generate totals per user.
Fastest option
SELECT
u.id
, (SELECT(COUNT(*) FROM blogs b WHERE b.user_id = u.id) as blogcount
, (SELECT(COUNT(*) FROM messages m WHERE m.user_id = u.id) as messagecount
FROM users u
Why you code does not work
SELECT u.id, count(b.id), count(m.id)
FROM users u
LEFT JOIN blogs b ON b.user_id = u.id <<-- 3 matches multiplies # of rows *3
LEFT JOIN messages m ON m.user_id = u.id <<-- 5 matches multiplies # of rows *5
GROUP BY u.id
The count will be off, because you are counting duplicate items.
Simple fix, but will be slower than option 1
If you only count distinct id's, you will get the correct counts:
SELECT u.id, count(DISTNICT b.id), count(DISTINCT m.id)
FROM users u
LEFT JOIN blogs b ON b.user_id = u.id
LEFT JOIN messages m ON m.user_id = u.id
GROUP BY u.id