I'm trying to display the username of the person who has submitted the most articles but I don't know how to do it using MySQL & PHP, can someone help me?
Here is the MySQL code.
CREATE TABLE users (
user_id INT UNSIGNED NOT NULL AUTO_INCREMENT,
username VARCHAR(255) DEFAULT NULL,
pass CHAR(40) NOT NULL,
PRIMARY KEY (user_id)
);
CREATE TABLE users_articles (
id INT UNSIGNED NOT NULL AUTO_INCREMENT,
user_id INT UNSIGNED mNOT NULL,
title TEXT NOT NULL,
acontent LONGTEXT NOT NULL,
PRIMARY KEY (id)
);
Here is the code I have so far.
$mysqli = mysqli_connect("localhost", "root", "", "sitename");
$dbc = mysqli_query($mysqli,"SELECT COUNT(*) as coun, user_id
FROM users_articles
GROUP BY user_id
ORDER BY coun DESC
LIMIT 1");
If you want to get the user's name, you should use the next query:
SELECT users.name, COUNT(users_articles.id) AS coun
FROM users_articles
LEFT JOIN users_articles ON users.id=users_articles.user_id
GROUP BY users_articles.user_id
ORDER BY coun DESC
LIMIT 1
select u.user_id, count(ua.id) as num_articles
from users u
left outer join users_articles ua
on u.user_id = ua.user_id
group by u.user_id
order by num_articles desc
The left outer join (as opposed to an inner join) ensures that all users are represented in the result, no matter if they have a record in users_articles or not.
EDIT: Since you only want the person who has submitted the most articles, you do not necessarily need the left outer join (as long as there is at least one user who has written any articles). For a complete list, it would be useful, however.
Whichever above queries given by geeks u use just DO NOT FORGET TO INCLUDE "username" field in select query as none of them has included the username field
What you want to do is a join.
The SQL query you need is this:
SELECT COUNT(*) as coun, users.user_id, username
FROM users_articles
INNER JOIN users
ON users_articles.user_id = users.user_id
GROUP BY user_id
ORDER BY coun DESC
LIMIT 1
I tested this and it works.
The result table contains the number of articles of the user, its user id and its username.
use like this,
SELECT COUNT(users_articles.*) as coun, users_articles.user_id, users.username
FROM users_articles, users
WHERE users_articles.user_id = users.user_id
GROUP BY users.user_id
ORDER BY coun DESC
SELECT COUNT(*) as coun, user_id, users.username
FROM users_articles, users
WHERE users_articles.user_id = users.user_id
GROUP BY user_id
ORDER BY coun DESC
LIMIT 1
Related
My tables
$sql="SELECT *
FROM addresses
LEFT JOIN users ON address_id = user_id
LEFT JOIN notes ON note_id = user_id
ORDER BY id DESC
LIMIT 1";
This is my SQL query, my task is to show the last records from 3 tables, but the table is blank, I don't know why,thanks in advance people :)
I guess the problem is coming from the ORDER BY id DESC .
Indeed, you have no column so called id.
You should probably remove this clause, in order to make your code work.
If you want to take the last records anyway, you can put an ORDER BY address_id DESC which will do the job !
The code directly edited :
$sql="SELECT *
FROM addresses
LEFT JOIN users ON address_id = user_id
LEFT JOIN notes ON note_id = user_id
ORDER BY adress_id DESC
LIMIT 1";
This may work:
SELECT a.address_id, u.user_id, n.note_id
FROM addresses a
LEFT JOIN users_addresses ua ON ua.ua_address_id = a.address_id
LEFT JOIN users u ON u.user_id = ua.ua_user_id
LEFT JOIN notes n ON n.note_user_id = u.user_id
ORDER BY a.address_id DESC
LIMIT 1
Here is the query to get all data from all the tables, not sure what do you mean last records from 3 tables, I can see four tables there:
SELECT *
FROM `addresses`
LEFT JOIN `users_addresses` ON `users_addresses`.`ua_address_id` = `addresses`.`address_id`
LEFT JOIN `users` ON `users`.`user_id` = `users_addresses`.`ua_user_id`
LEFT JOIN `notes` ON `notes`.`note_user_id` = `users`.`user_id`;
So I am very bad at this anyway right now I have this code
$test = "SELECT `status`,`pubdate` FROM `status` ORDER BY `pubdate` DESC";
$stmt = $db->prepare($test);
$stmt->execute();
while($row = $stmt->fetch(PDO::FETCH_ASSOC)){
echo "<section class='statusar'>"."<article>";
echo $row['status'];
echo $row['pubdate'];
echo "</article></section>";
}
and it shows the post but now I want to take users first name from another table and display it with the post. How do I do it?
The two tables I have look like this
This is the table with the post
Status_id int unsigned auto_increment primary
user_id int unsigned index
status varchar(600)
pubdate datetime
This is the other table
user_id int unsigned auto_increment primary index
firstname varchar(30)
surname varchar(30)
username varchar(30) unique
password varchar(90)
I have done so they have a relation between the user_ids
EDIT
I think I figured it out because now it works :D
So now when I use
SELECT status, pubdate,firstname,surname FROM status INNER JOIN user ON status.user_id = user.user_id ORDER BY status.pubdate DESC
It displays all the things I want and I also tried
SELECT * FROM status INNER JOIN user ON status.user_id = user.user_id ORDER BY status.pubdate DESC";
Which also works thanks for the help guys :D
Just use an inner join:
SELECT s.status, s.pubdate, u.firstname
FROM status s
INNER JOIN usertable u ON s.user_id = u.user_id
ORDER BY s.pubdate DESC
A Visual Explanation of SQL Joins
This assumes the user_id exists in the usertable. If that might not be the case, you'd want to use an outer join instead.
Consider a group table and member-group relationship table as
CREATE TABLE group (
group_id int(11) not null auto_increment,
title varchar(50),
status ENUM('private', 'public'),
PRIMARY KEY(group_id)
);
CREATE TABLE group_map (
group_map_id int(11) not null auto_increment,
group_id int(11) REFERENCES group(group_id),
user_id int(11) REFERENCES user(user_id),
PRIMARY KEY(group_map_id)
);
Now in the group page, how can I show the content if
1. Group is public
OR
2. user is member of that group (user_id comes from $_SESSION login,
and we check if the current group_id && user_id exists in group_map table).
Here's how to retrieve a list of all groups that user 1 can access, complete with group name:
SELECT g.group_id, g.name
FROM `group` g
LEFT JOIN group_map gm
ON gm.group_id = g.group_id
WHERE g.status = 'public'
OR gm.user_id = 1
Here's an alternative, using UNION.
(SELECT g.group_id, g.name
FROM `group` g
WHERE g.status = 'public')
UNION
(SELECT g.group_id, g.name
FROM `group` g
JOIN group_map gm
ON gm.group_id = g.group_id
WHERE gm.user_id = 1)
They them both out for size.
Notice the backticks around the group tablename because GROUP is a reserved word in MySQL.
You should try this...
SELECT g.*,gm.* FROM group g INNER JOIN group_map gm ON g.`group_id` = gm.`group_id`
First, if I understand right what you want, you don't need 2-nd table. You can use Users table.
If group is private I was doin it that way
SELECT tblGroups.*, tblUsers.*
FROM `tblGroups`, `tblUsers`
WHERE tblGroups.id=tblUsers.group AND // here you put what you need to open //
otherwise group is public just this
SELECT tblGroups.*
FROM `tblGroups`
WHERE // here you put what you need to open //
Im making a codeigniter webapp where users can add each other in a contactslist.
The table looks like this:
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_1` int(11) NOT NULL,
`user_2` int(11) NOT NULL,
`accepted` tinyint(2) NOT NULL,
PRIMARY KEY (`id`)
The userid for the user that makes the request to add the contact is always stored in user_1 column. The other users userid is stored in user_2. user_2 then has to accept the request and the 'accepted' column gets updated to 1.
I want to list all contacts that are accepted (WHERE accepted = 1) in a html table, and the contact requests (accepted = 0) in another.
My question is: How can i make a mysql query that selects all the rows and just get the userid from the contact? Its a problem since they can be in either user_1 or user_2 (Depending on if they requested or accepted).
Should i change the db table in some way to achieve this. Or could i make a query (active rcords preferably) that accomplish this?
Any help is appreciated
Thanks in advance
George
Update:
So the final query looks like this:
SELECT DISTINCT users.id, users.username, contacts.accepted
FROM users
LEFT JOIN contacts ON users.id = contacts.user_1
WHERE contacts.user_2 = ' . $this->session->userdata('user_id') . '
UNION DISTINCT
SELECT DISTINCT users.id, users.username, contacts.accepted
FROM users
LEFT JOIN contacts ON users.id = contacts.user_2
WHERE user_1 = ' . $this->session->userdata('user_id')
And works exactly as i described :)
Use a UNION query. See the documentation.
SELECT DISTINCT user_1 userid FROM user WHERE accepted = 1
UNION DISTINCT
SELECT DISTINCT user_2 userid FROM user WHERE accepted = 1
About the join, you'd use something like below for each part of the UNION
SELECT DISTINCT users.userid, users.username, contacts.accepted
FROM users
LEFT JOIN contacts ON users.userid = contacts.user_1
WHERE contacts.user_2 = ?
Shouldn't the contactlist be owned by the user?
create table Contactlist (
OwnerID int, -- ID of the owning User
ContactID int, -- ID of the contact User
Accepted bool)
-- With composite primary key on OwnerID, ContactID
This way the query would be
select * from User
left outer join Contactlist on User.ID = Contactlist.OwnerID
left outer join User as Contact on Contactlist.ContactID = Contact.ID
Sorry... Overthunk the select ;)
select * from Contactlist
inner join User on Contactlist.ContactID = User.ID
where Contactlist.OwnerID = <the querying users ID>
(MSSQL syntax)
You can use queries but it will create problems later on I guess as I have also faced this problem before. You can insert new entries in the same table when a user accepts the request and mark the new record as accepted but this time the user_1 becomes user_2 and vice versa.
Alias with joins is waht I think you are asking.
Something like.
Select c.id, uRequest.UserName, uRequested.UserName From Contacts c
inner join Users As uRequest On c.User_1 = uRequest.id
inner join Users As uRequested On c.User_2 = URequested.id
Where accepted = 1
will give you all contacts where the request has been accepted.
Let's say I have two tables, users and notes. Let's say the schemas look like this:
users
id, name, field2, field3
notes
id, user_id, subject, heading, body, timestamp
What I want to do is select every user, and the LATEST (just 1) note posted by each user based on the timestamp to show in an overview report.
How would I go about doing this? Please note that the DB is MySQL.
Thanks!
select users.name, notes.subject, notes.heading, notes.body
from users, notes
where users.id = notes.user_id
and notes.timestamp = (select max(timestamp) from notes where user_id = users.id)
select u.id, u.name, n.id as note_id, n.subject, n.heading, n.body, n.timestamp
from users u
left outer join (
select user_id, max(timestamp) as timestamp
from notes
group by user_id
) nm
left outer join notes n on nm.user_id = n.user_id and nm.timestamp = n.timestamp
Note that this could potentially return duplicates if the user has two notes with the exact same timestamp. I have assumed this is not the case.
SELECT *
FROM `users`
LEFT JOIN `notes`
ON `user_id` = `users`.`id`
WHERE `notes`.`timestamp` = (
SELECT MAX(`timestamp`)
FROM `notes` AS `notes_1`
WHERE `notes_1`.`user_id` = `notes`.`user_id`
)