how can I find the total records in this case:
I have a table 'users', a table 'messages' and a table 'groups'. A user can sent a message, and that will be stored in the table 'messages'. Each user can be a member of one group. Now I would like to show the total messages sent by all users in the group on the group-details-page. How can I get all the users in the group and count their messages? What is the best and fastest way to do that?
I can't work with Joins, so this doesn't work. I don't know how to fix it.
SELECT COUNT(Message_id) AS total_messages, d.Userid FROM messages AS
d LEFT JOIN users AS s ON (s.Groupid=$groupid) WHERE
s.Groupid=$groupid
Thanks!
If you need table structure:
** users **
Userid
Groupid
** groups **
Groupid
Some_details
** messages **
Messageid
Userid
Subject
Content
If you're looking for total messages without needing to know per user, try
SELECT COUNT(messages.Messageid) as total_messages
FROM messages
INNER JOIN users ON messages.Userid = users.Userid
WHERE users.Groupid = $groupid
Make sure you're indexing the messages.Userid field as well if you'll be doing a lot of querying based on it.
Needing a count per user try
SELECT
COUNT(messages.Messageid) as num_messages,
messages.Userid
FROM messages
INNER JOIN users ON messages.Userid = users.Userid
WHERE users.Groupid = $groupid
GROUP BY users.Userid
If you want all users in a particular group with their total messages then try out this
SELECT messages.Userid, COUNT(messages.Messageid) as total_messages
FROM messages
INNER JOIN users ON messages.Userid = users.Userid
WHERE users.Groupid = $groupid GROUPBY messages.Userid
Select Groupid,Some_details,count(Messageid) as count_message from groups Left join users On
users.Groupid = groups.Groupid left join messages on messages.Userid = users.users.Userid GROUP BY Groupid
Related
my query looks like that:
SELECT
count(users.id)
FROM users
LEFT JOIN mail_sender_jobs_actions ON mail_sender_jobs_actions.userID = users.id
LEFT JOIN table2 ON table2.userID = users.id
LEFT JOIN table3 ON table3.userID = users.id
WHERE {$flexibleWhereClause}
Now, the mail_sender_jobs_actions table CAN (doesnt need to return anything) return multiple entries. I dont want to group the results but still limit the returns of mail_sender_jobs_actions to 1 so I dont get duplicates... Otherwise the count wouldnt work properly.
Scraped the whole web and found nothing working for me as I want to keep the where clause flexible. Any solution?
EDIT
so to explain the situation. We have a table with users (users). We have a table with actions (mail_seder_jobs_actions). We have other tables related to that query which are not relevant (table1, table2, table3)
If a user does an action, an entry is being created in the actions table.
The where clause is flexible, meaning it is possible that somebody wants to only show users with a specific action.
It is also possible that an action is not relevant to the user, so this entry gets ignored.
With where criteria you have there is no point using left join, since the where criteria applies to the table on the right hand side, effectively turning the left join into an inner join.
Apparently yo do not use any columns from the right hand side table, so instead of using joins, I would use an exists subquery.
SELECT
1 as count,
users.email
FROM users
WHERE EXISTS (SELECT 1
FROM mail_sender_jobs_actions
WHERE mail_sender_jobs_actions.userID = users.id
AND mail_sender_jobs_actions.type = '1'
AND mail_sender_jobs_actions.jobID = '106'
AND {$flexibleWhereClause})
However, there is little point in having the count() because it will always return 1. If you want to count how many records each user has in the mail_sender_jobs_actions table, then you have to use left join, group by, and move the where criteria into the join condition:
SELECT
count(mail_sender_jobs_actions.userID),
users.email
FROM users
LEFT JOIN mail_sender_jobs_actions ON mail_sender_jobs_actions.userID = users.id
AND mail_sender_jobs_actions.type = '1'
AND mail_sender_jobs_actions.jobID = '106'
AND {$flexibleWhereClause}
GROUP BY users.email
I want to have some help creating my query to get information from three different tables sharing information in common.
My first table is:
auctions
id title description user_id(who posted it)
My second table is:
bids
id user_id bid auction_id owner_id
My third table is:
users
id username X XX XXX XXXX
...and my SQL is as follows however it's not returning any results:
SELECT auction_bids.user_id AS applicant, auction_bids.*, auctions.title FROM auction_bids, auctions
WHERE auctions.user_id=".$_SESSION['userid']."
INNER JOIN users ON auction_bids.user_id = users.id
WHERE auction_bids.owner_id = ".$_SESSION['userid']."
What I need is to capture the auction's title, username who bidded on the auction and the bid. the auction has to have a bid and posted by the user who owns the $_SESSION['userid'].
Any help is appreciated.
You have two different 'where' statements, which may just need combining;
SELECT auction_bids.user_id AS applicant, auction_bids.*, auctions.title FROM auction_bids, auctions
INNER JOIN users ON auction_bids.user_id = users.id
WHERE auction_bids.owner_id = ".$_SESSION['userid']." AND auctions.user_id=".$_SESSION['userid']."
However, I'm not sure this is really what you want, as it will return only records where the specific user both 'owns' the item AND has bidded on it (both based on the userid session), rather than displaying all records from different people who have bidded on an item 'owned' by the user.
Something like: ?
SELECT auction_bids.user_id AS applicant, auction_bids.*, auctions.title FROM auction_bids, auctions
INNER JOIN users ON auction_bids.user_id = users.id,
WHERE auction.owner_id = ".$_SESSION['userid']."
Hope this points you in the right direction!
you have 2 where clauses, that is incorrect. I have revised your query based on your requirements.
SELECT auction_bids.user_id AS applicant, auction_bids.*, auctions.title
FROM auction_bids, auctions
INNER JOIN users ON auction_bids.owner_id = users.id
WHERE auction_bids.owner_id = ".$_SESSION['userid']."
AND auctions.user_id=auctions_bids.owner_id
I have the userids of people who have joined a group in one table but not their names thatlie in another table. So I think I need to do a join. I'm starting with groupid that describes the grouop.
Table 1, groupmem has groupid and userid for the members.
Table 2, users has userid and username
The users table has every user. The groupmem only has some who have joined groups.
SQL statement should be something like following but can't get it to work.
select users.name
FROM users,groupmem
LEFT JOIN users
on groupmem.userid=users.userid
WHERE groupmem.groupid = 22
22 being some value..
Thinking maybe where clause is in wrong place or I am using wrong type of join but or not using on correctly but, in any case, can't get it to work. Thx for any suggestions:
Try:
SELECT u.username
FROM `users` u
LEFT JOIN `groupmem` g
ON u.userid = g.userid
WHERE g.groupid = 22
This should do the trick:
SELECT users.name
FROM groupmem
LEFT JOIN users ON groupmem.userid = users.userid
WHERE groupmem.groupid = 22
Your query seems to be quite right - assuming I guessed your table-structure right.
I have tables as below.
Table Messages
message_id
parent_id
forum_id
user_id
Table Users
user_id
username
pass
How to query a user, and display the count of their messages with their username?
My query:
select count(subject), user_id from messages group by user_id;
The problem is that it only displays user_id and count of messages but no username. How do I make it display the name of the user?
You need to join the users table into your query:
select count(*), username
from messages, users
where users.user_id = messages.user_id
group by users.user_id;
SELECT username, COUNT(*) FROM messages M
JOIN users U USING (user_id)
GROUP BY U.user_id
This takes care of a scenario where two different user_id have the same username in the users table. Also this query is MySQL specific and may not work with other RDBMS.
I think this is the query you want.
$query = "SELECT u.username, COUNT(*) as total_count FROM messages m INNER JOIN users u ON m.user_id = u.user_id GROUP BY U.user_id"
Here total_count gives the total count of messages grouped by user id to avoid joining of same usernames.
Use below. I believe it will work.
SELECT messages.user_id, users.username, count(*)
FROM messages, users
WHERE messages.user_id = users.user_id
Good Luck!!!
I have two tables called messages and users. In the messages table, there's a field which is a foreign key to the users table that is basically the users ID. I am trying to retrieve results from the messages table using a SELECT query, but I want the users username rather than their user ID. This SQL is wrong but I think it gets across the idea of what I'm trying to do:
SELECT (SELECT username FROM `users` WHERE u_id=?), message, sent FROM `messages` WHERE r_id=? AND sent > ?
Basically, I want to use the users ID stored in the messages table to get the users username to be returned AND get results from the messages table in one query.
I think JOINs are the tool for this, but I have very little bar no SQL experience.
Thanks.
You want to JOIN the two tables together, using the common u_id column.
SELECT u.username, m.message, m.sent
FROM messages m
INNER JOIN users u
ON m.u_id = u.u_id
WHERE m.r_id = ?
AND m.sent > ?
This is the case for an inner join:
select
u.username,
m.message,
m.sent
from
messages m
inner join users u on
m.u_id = u.u_id
where
m.r_id = ?
and u.u_id = ?
and m.sent > ?
What you're doing here is taking the messages table and saying, "Okay, grab me everything in the users table where the u_id column from messages equals the u_id column from users.
The where clause then filters your results down based on the parameters you want to pass it.
You can join tables ad nauseum, so you don't have to do just one, for future reference.
If you'd like to read more about joins and the different types, I highly encourage you to read Atwood's post on it here.
You can join two tables like this too:
SELECT
u.username,
m.message,
m.sent
FROM
messages m,
users u
WHERE
m.r_id=? AND
m.sent > ? AND
m.u_id = u.u_id
m.u_id is user id in messages table
You can refactor the query slightly like this:
select
u.username,
m.message,
m.sent
from
(
select u_id,message,sent
from messages
where r_id = ?
and sent > ?
) m
inner join
(
select u_id,username
from users
where u_id = ?
) u using (u_id);
You need to make sure you have a compound index on r_id and sent
ALTER TABLE messages ADD INDEX (r_id,sent);
Your query needs only slight correction and then it's equivalent to a LEFT JOIN (or INNER JOIN, exactly as #Joe Stefanelli's answer if messages.u_id is never NULL):
SELECT
(SELECT username FROM `users` WHERE u_id = messages.u_id) AS username
, message
, sent
FROM messages
WHERE r_id = ?
AND sent > ?