Update multiple rows with different values in MySQL database table - php

I'm trying to select commenter from a table called comments then select username from a table called users using a where clauses from the details from the first table.
After that update comments set username to the usernames obtained from table 2.
This is my code:
<?php
include("connection.php") ;
$sql=mysqli_query($link, "SELECT * FROM comment ORDER BY id ASC" ) ;
while($row=mysqli_fetch_assoc($sql)){
$commenter=$row['commenter'] ;
$sqli=mysqli_query($link, "SELECT * FROM users WHERE fullname='$commenter' ORDER BY id ASC" ) ;
while($rows=mysqli_fetch_assoc($sqli)){
$username=$rows['username'] ;
$sql_u=mysqli_query($link, "UPDATE comment SET username='$username' WHERE commenter='$commenter' " ) ;
}
}
?>
The code above only updates one row

Here is a small correction of Barmar answer
UPDATE comment c
JOIN users u ON u.fullname = c.commenter
SET c.username = u.username
u.fullname = c.commenter instead of comment

Related

php mysql query combination

I first search all questions info. from "question" table including title, content, user etc.
the Code:
$sql = "select * FROM question where id>0 ORDER BY id ASC";
$result1 = mysql_query($sql);
$res=Array();
And then I want to search the user's point from "user" table. So I must search point for each user in each row from the result1
The Code:
while($rows=mysql_fetch_assoc($result1))
{
$res[]=$rows;
$user = $rows['user'];
$sql2 = "select point from user where name='$user'";
$result2 = mysql_query($sql2);
}
My problem is how to combine all the users' point(result2) with the questions info.(result1) together so that I can return a json for each row.
Use left join, as my understanding this work for you
$sql = "SELECT q.*, u.point AS point FROM question AS q LEFT JOIN user AS u ON q.user = u.name WHERE q.id > 0 ORDER BY q.id ASC";
$result = mysql_query($sql);
It's better go with the joins here i am giving you the query.i hope it may helps you
select * from question q,user u where q.id>0 ORDER BY id ASC
try something like this:using left join
select question.*,user.point FROM question left join user on user.name= question.name where id>0 ORDER BY id ASC

Query inside of another query?

I've searched and found ways to do queries inside queries, but I have not found the right answer.
What I am trying to do is to fetch comments from the table called users_profiles_comments and by doing that I will get the field of '.$member["author"].'. Then I want to show who made the comment with their rank and a display picture.
But because there is no user details stored in the comments table because its for comments, I need to create a query inside of my query result where I can have this:
"SELECT * FROM users WHERE username = $member['author'] ORDER BY `id` ASC"
The '.$member["author"].' value comes from the main query but I need it so it can find fields in my users table.
$sql = "SELECT * FROM users_profiles_comments WHERE postid = '1' ORDER BY `id` ASC";
$stm = $dbh->prepare($sql);
$stm->execute();
$users = $stm->fetchAll();
foreach ($users as $row) {
print '
<img src="'.$member["profilepic"].'" style="float:left;margin-right:10px;" width="80px" height="85pxm">
<h4>'. $row["author"] .'
<small>'. $row["date"] .'</small>
</h4>
<p>'. $row["content"] .'</p><hr> </a></li>';
}
echo '
</div>
';
I hope you understand.
Edit:
The database.
users Table
http://img855.imageshack.us/img855/4387/qyjl.png
users_profiles_comments table
http://i.imgur.com/aKRF5MN.png
But because there is no user details stored in the comments table because its for comments
This is good. You do not want to have your database information duplicated in both tables (de-normalized data) - there is no need.
Generally a foreign key is added to inverse side of the relationship. This would mean you have a user_id column within your comments table, allowing you to select the data in one query using a JOIN
SELECT comment.*, user.name AS comment_author
FROM comment
INNER JOIN user ON user.id = comment.user_id
WHERE user.id = 123
Edit - I flipped to JOIN to return comments rather than users, (as you said "to fetch comments") however both ways will work, it just depends which side of the relationship you are on.
Edit 2 To respond to your comment;
How would I be able to show this on my PHP code on the result?
you can be more specific with the above query (not use *) and render it as follows :
$sql = "
SELECT
comment.`date` as comment_date,
comment.content,
user.name AS author_name,
user.profilepic as author_pic
FROM
users_profiles_comments as comment
INNER JOIN
user ON user.id = comment.user_id
WHERE
comment.postid = 1
";
//...
$comments = $stmt->fetchAll();
foreach ($comments as $comment) {
echo '<img src="' . $comment['author_pic'] . '"/>';
echo '<h4>' . $comment['author_name'] . '<small>' . $comment['comment_date'] .'</small></h4>';
echo '<p>' . $comment['content'] . '</p>';
}
You can select member name in SQL statement. You can try this query, this query will bring all the information from two table if users.username = users_profiles_comments.author
WAY 1:
SELECT t1.*, t2.* FROM
(
SELECT * FROM users WHERE username = '.$member["author"].' ORDER BY `id` ASC
) AS t1
LEFT JOIN
(
SELECT * FROM users_profiles_comments WHERE postid = '1' ORDER BY `id` ASC
) AS t2
ON t1.username = t2.author
Finally, do your foreach to print
===================================================================
WAY 2:
You can try this also-
SELECT *,
(SELECT profilepic FROM users WHERE users.username = users_profiles_comments.author) AS profilepic
FROM users_profiles_comments WHERE postid = '1' ORDER BY `id` ASC
And print profilepic using $row['profilepic'] in your foreach loop
=====================================================================
WAY 3:
SELECT t1.*, t2.* FROM
(
SELECT * FROM comments WHERE postid = '1'
) AS t1
LEFT JOIN
(
SELECT * FROM users
) AS t2
ON t1.author = t2.username
What I understand is that you need to get information about the user from another table called user_profile_comments, based on the user id (correct me if wrong: :-)). Use a left outer JOIN to fetch data from another table, limited on user id.
See http://www.w3schools.com/sql/sql_join.asp for more info.

Select data from 2 MySQL tables - PHP

I have two tables:
Table 1
contacts
id
email
name
lastname
postcode
straat
huisnr
woonplaats
klantnummer
bsn
land
debiteurnummer
Table 2
contacts_group
id
mail
group_name
How can I select and order this 2 tables in one query. I've tried union and left join, but did not work.
$result = mysqli_query($database->connection,
"SELECT *
FROM contacts
WHERE owner = '$session->username'
ORDER BY name ASC ,bedrijfsnaam ASC")
or die(mysqli_error());
while($roww = mysqli_fetch_array($result)){
echo $roww['email'];
echo $roww['name'];
}
Table contacts_group:
$result = mysqli_query($database->connection,
"SELECT *
FROM contacts_group
WHERE owner = '$session->username'
ORDER BY group_name ASC")
or die(mysqli_error());
while($roww = mysqli_fetch_array($result)){
echo $roww['mail'];
echo $roww['group_name'];
}
Escape your variables. You should not put the php variable unescaped in sql query. You can suffer from sql injections.
If you want to join two tables by foregin key you can do:
SELECT * FROM contacts, JOIN contacts_group ON contacts_group.id = contacts.group_id
WHERE contacts.owner = '$session->username' ORDER BY contacts.name
But you are missing group_id in contacts table or some foregin key to connect two tables.
Before do it read this topic, after try to use mysql join construction

mysql return the total of rows for each user_id

$sql = "SELECT * FROM books LEFT JOIN users
ON books.readby=users.user_id WHERE users.email IS NOT NULL";
$result = mysql_query($sql);
while($row = mysql_fetch_array($result))
{
echo $row['readby']. " - read 10 books";
} //while ends
this is the code I have so far. I am trying to retrieve the number of books read by each user
and echo the results. echo the user_id and number of books he/she read
books table is like this : id - name - pages - readby
the row readby contains the user id.any ideas/suggestions? I was thinking about using count() but Im not sure how to go about doing that.
A subquery can return the count of books read per user. That is left-joined back against the main table to retrieve the other columns about each user.
Edit The GROUP BY had been omitted...
SELECT
users.*,
usersread.numread
FROM
users
/* join all user details against count of books read */
LEFT JOIN (
/* Retrieve user_id (via readby) and count from the books table */
SELECT
readby,
COUNT(*) AS numread
FROM books
GROUP BY readby
) usersread ON users.user_id = usersread.readby
In your PHP then, you can retrieve $row['numread'] after fetching the result.
// Assuming you already executed the query above and checked errors...
while($row = mysql_fetch_array($result))
{
// don't know the contents of your users table, but assuming there's a
// users.name column I used 'name' here...
echo "{$row['name']} read {$row['numread']} books.";
}
You can use count() this way:
<?php
$count = mysql_fetch_array(mysql_query("SELECT COUNT(`user_id`) FROM books LEFT JOIN users ON books.readby=users.user_id WHERE users.email IS NOT NULL GROUP BY `user_id`"));
$count = $count[0];
?>
Hope this helps! :)

How to get information from 2 tables at once in PHP and MySQL?

<?php
include('includes/config.php');
$topi = $_GET['id']; //id of url
mysql_select_db("ban", $con);
$query = "SELECT * FROM `basic` WHERE id = '$topi' LIMIT 0, 30";
$result = mysql_query($query) or die(mysql_error());
$row = mysql_fetch_array($result) or die(mysql_error());
$aa = $row['item'];
$cc = $row['moreinfo'];
$dd = $row['contactinfo'];
$ff = $row['id'];
In this script, I get information from the table basic, but I want to retrieve data from another table named users. How can I retrieve data from two tables at once?
users table consists of following columns:
email
username
ID
You need to JOIN the two tables on a common value, called a foreign key. Once you've posted the structure of the users table as requested in the comments, I can provide a more complete example.
EDIT: See example. This calls explicit column names instead of SELECT *.
$query = "SELECT
basic.id,
basic.item,
basic.moreinfo,
basic.contactinfo,
users.email,
users.username
FROM basic JOIN users ON basic.id = users.id
WHERE id = '$topi'
LIMIT 0 , 30";
You would use a JOIN onto the other table.
$query = "SELECT *
FROM basic b
JOIN users u ON b.user_id = u.user_id
WHERE id = '$topi'
LIMIT 0, 30";
Something like that, but based on your fields.
Please Note: the ON clause specifies what you will be looking for a match on.

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