I have three tables:
users: id, name
shifts: id, date_start, date_end
users_shifts: user_id, shift_id
I want to get all the users who have done n shifts in a specific date range, where n can be any integer (also 0!).
I can get all the users with the number of shifts they have done like this:
SELECT
users.*,
COUNT(users_shifts.user_id) AS nr_shifts
FROM
users
LEFT JOIN
users_shifts ON users.id = users_shifts.user_id
GROUP BY
users.id
I have no clue how to:
1) add the date range to this query
2) limit the results to a specific nr_shifts
Any help is greatly appreciated.
SELECT
users.*,
COUNT(users_shifts.user_id) AS nr_shifts
FROM
users
LEFT JOIN
users_shifts ON users.id = users_shifts.user_id
WHERE shifts.date_end = '10/OCT/2012'
GROUP BY
users.id
Order by users.id
LIMIT 10
A second join doesn't do what you need?
SELECT
users.*,
COUNT(users_shifts.user_id) AS nr_shifts
FROM
users
LEFT JOIN
users_shifts ON users.id = users_shifts.user_id
LEFT JOIN
shifts ON shifts.id = users_shifts.shift_id
WHERE
shifts.date_start BETWEEN 2013-06-01 and 2013-06-30
OR ISNULL(shifts.date_start)
GROUP BY
users.id
Related
i want to display three replies from each user i have in my users table, so for instance if i have 3 users and each of them had replied to lets say 10 messages, i want my query to only retrieve 9 replies and not all of the replies in my messages_reply table.
heres what i tried:
$replyquery="select *
from messages_reply
LEFT JOIN users
ON messages_reply.from_id=users.id
GROUP BY messages_reply.id LIMIT 3";
i know that what i wrote means that bring me 3 replies only, so how do i bring 3 replies from each user in my users table?
In many databases, you can use row_number() for this:
select *
from (
select mr.*, u.*, row_number() over(partition by u.id order by mr.id desc) rn
from messages_reply mr
inner join users u on mr.from_id = u.id
) t
where rn <= 3
If you are running MySQL < 8.0, as I suspect from the lax use of group by in your query:
select mr.*, u.*
from messages_reply mr
inner join users u on mr.from_id = u.id
where mr.id >= (
select mr1.id
from messages_reply mr1
where mr1.from_id = u.id
order by mr1.id desc
limit 2, 1
)
This gives you the 3 message replies with the greatest id for each user.
Query not tested, just a concept
SELECT *
FROM users
LEFT JOIN (
SELECT *
FROM messages_reply
WHERE from_id = users.id
ORDER BY <your wanted order field> DESC
LIMIT 3) replies
ON users.id = replies.from_id
I have two table users and transactions. transactions table has relation with users two table format like below
users
id name email created
1 a a#mail.com 12-03-01
2 b b#mail.com 11-03-01
Transactions
id user_id balance
1 1 250
2 1 550
3 2 50
4 2 1000
I need last inserted users balance from transactions table with all users information. I am new in sql.
So I have tried below code
select * from transactions
where id in (select max(id) from transactions group by user_id)
INNER JOIN users on transactions.user_id=users.id
It's giving me syntax error near inner join.Have I made any mistake in inner join ? or I am in wrong direction ?
If you only want the balance, then a correlated subquery might be faster:
select u.*,
(select t.balance
from transactions t
where t.user_id = u.id
order by t.id desc
limit 1
) as MostRecentBalance
from users u;
For maximum performance, you want an index on transactions(user_id, id desc, balance).
The reason this is faster is because it avoids the aggregation on the entire transactions table. This is even more important if you are only selecting a subset of users.
EDIT:
I originally read this question as one row per user. However, if you only want one row returned -- for the last insert into transactions -- then a simpler method is:
select u.*, t.balance
from users u join
transactions t
on u.id = t.user_id
order by t.id desc
limit 1;
The JOIN should be part of the FROM statement so it should look more like the code below.
select *
from transactions ts
INNER JOIN users
ON (transactions.user_id=users.id)
where ts.id in
(
select max(transactions.id)
from transactions
group by user_id
);
edited to clarify which id is in use as per Gordons suggestion
2 simple methods.
A sub query to get the lastest transaction, and from that all the transaction details and then the user
SELECT users.*
FROM users
INNER JOIN transactions
ON users.id = transactions.user_id
INNER JOIN
(
SELECT MAX(id) AS max_id
FROM transactions
) sub0
ON transactions.id = sub0.max_id
Or you could try ordering by the id descending with a limit of 1:-
SELECT users.*
FROM users
INNER JOIN transactions
ON users.id = transactions.user_id
ORDER BY transactions.id DESC
LIMIT 1
EDIT
To get the last transaction for all users then you could use the following:-
SELECT *
FROM users
INNER JOIN transactions
ON users.id = transactions.user_id
INNER JOIN
(
SELECT user_id, MAX(id) AS max_id
FROM transactions
GROUP BY user_id
) sub0
ON transactions.id = sub0.max_id
ON transactions.user_id = sub0.user_id
There are three tables. user, like, comment. Table like and comment has rows associated to user. I need all users with their associated row count from table like and comment. It's easy to do when there is only one table associated. However, here is my query.
SELECT u.id as id, u.display_name as displayName,
COUNT(x.user_id) as likeCount,
COUNT(y.user_id) as commentCount
FROM `user` u
LEFT JOIN
`like` x ON x.user_id = u.id
LEFT JOIN
`comment` y ON y.user_id = u.id
GROUP BY u.id
Table relationships:
One user has many likes
One user has many comments
commentCount is giving correct rows count, but likeCount giving wrong rows count. Please don't post answer which uses sub queries. I want it with only ONE SELECT clause. I am using MySQL. TIA
You can get the user count per individual table, like this:
SELECT user, COUNT(*) AS t1Count
FROM table1
GROUP BY user;
SELECT user, COUNT(*) AS t2Count
FROM table2
GROUP BY user;
Then you can join those two to the Users table to get the count of each. You should use COALESCE() to return null values with 0:
SELECT u.id, COALESCE(t1.t1Count, 0), COALESCE(t2.t2Count, 0)
FROM users u
LEFT JOIN(
SELECT user, COUNT(*) AS t1Count
FROM table1
GROUP BY user) t1 ON u.id = t1.user
LEFT JOIN(
SELECT user, COUNT(*) AS t2Count
FROM table2
GROUP BY user) t2 ON u.id = t2.user;
Here is an SQL Fiddle example.
I need to count the amount of users that have have answered all of those 3 profile_options (so they have at least 3 records in the profile_answers table).
SELECT COUNT(DISTINCT(users.id)) users_count
FROM users
INNER JOIN profile_answers ON profile_answers.user_id = users.id
WHERE profile_answers.profile_option_id IN (37,86,102)
GROUP BY users.id
HAVING COUNT(DISTINCT(profile_answers.id))>=3
The problem is that this query is return a table with rows for each user and how many they answered (in this case always 3). What I need is to return just one row that has the total number of users (so the sum of all rows of this example)
I know how to do it with another subquery but the problem is that I am running into "Mysql::Error: Too high level of nesting for select"
Is there a way to do this without the extra subquery?
SELECT SUM(sum_sub.users_count) FROM (
(SELECT COUNT(DISTINCT(users.id)) users_count
FROM users
INNER JOIN profile_answers ON profile_answers.user_id = users.id
WHERE profile_answers.profile_option_id IN (37,86,102)
GROUP BY users.id
HAVING COUNT(DISTINCT(profile_answers.id))>=3)
) sum_sub
Please give this query a shoot
SELECT COUNT(DISTINCT(u.id)) AS users_count
FROM users AS u
INNER JOIN (
SELECT user_id, COUNT(DISTINCT profile_option_id) AS total
FROM profile_answers
WHERE profile_option_id IN (37,86,102)
GROUP BY users.id
HAVING COUNT(DISTINCT profile_option_id) = 3
) AS a ON a.user_id = u.id
If you have lots of data in your tables, you will get a better/faster performance by using temporary tables like so
CREATE TEMPORARY TABLE a (KEY(user_id)) ENGINE = MEMORY
SELECT user_id, COUNT(DISTINCT profile_option_id) AS total
FROM profile_answers
WHERE profile_option_id IN (37,86,102)
GROUP BY users.id
HAVING COUNT(DISTINCT profile_option_id) = 3;
Then your final query will look like this
SELECT COUNT(DISTINCT(u.id)) as users_count
FROM a
INNER JOIN on a.user_id = u.id
Unless there is a need to join the users table you can go with this
SELECT COUNT(*) AS users_count
FROM (
SELECT user_id, COUNT(DISTINCT profile_option_id) AS total
FROM profile_answers
WHERE profile_option_id IN (37,86,102)
GROUP BY users.id
HAVING COUNT(DISTINCT profile_option_id) = 3
) AS a
Should you need another solution, please consider providing us you EXPLAIN EXTENDED for the query and the table definitions along with a better problem description.
I hope this helps
You can give the queries a name using the AS clause. See the updated query below.
SELECT SUM(sum_sub.users_count) FROM (
(SELECT COUNT(DISTINCT(users.id)) as users_count
FROM users
INNER JOIN profile_answers ON profile_answers.user_id = users.id
WHERE profile_answers.profile_option_id IN (37,86,102)
GROUP BY users.id
HAVING COUNT(DISTINCT(profile_answers.id))>=3)
) as sum_sub
You should not group by on a field not present in select statement.
select id, count(*) from users group by id is fine
select count(id) from users group by id is NOT
Regarding your query I think the link to user table is not necessary. Just using foreign key should be fine.
Try this one:
select count(*) from
(SELECT users_id count(*) as cnt
FROM profile_answers
INNER JOIN users ON profile_answers.user_id = users.id
WHERE profile_answers.profile_option_id IN (37,86,102)
group by users_id
having count(*) >3)
SELECT users.id, COUNT(?) FROM orders
INNER JOIN users ON (orders.user_id = users.id)
WHERE ??
How can i output:
UserID: 123 has made 22 orders
UserID: 124 has made 2 orders
and so on?
I would like to only grab the users that has one or more orders, and exclude those with 0 orders.
SELECT users.id, COUNT(*) FROM orders
INNER JOIN users ON (orders.user_id = users.id)
group by users.id
having count(*)>=1
SELECT users.id, COUNT(*) FROM orders
INNER JOIN users ON (orders.user_id = users.id)
GROUP BY users.id
HAVING count(*) >= 1