I'm trying to get the top 5 users in my database according to their post count
<?php
$data = mysql_query("SELECT COUNT(*) FROM pins ORDER BY user_id ASC LIMIT 5")
or die(mysql_error());
while($info = mysql_fetch_array( $data ))
{
Print "<table><tr><td>";
Print "".$info['user_id']."";
Print "</td></tr></table>";
}
?>
This is a code I have adapted which works for individual users with a WHERE user_id='999' clause. But how do I change it to get the top 5?
Use GROUP BY:
SELECT user_id
FROM pins
GROUP BY user_id
ORDER BY COUNT(*) DESC
LIMIT 5
Related
I thought this would be simple but I'm having a tough time figuring out why this won't populate the the data array.
This simple query works fine:
$queryPrice = "SELECT price FROM price_chart ORDER BY id ASC LIMIT 50";
$resultPrice = mysqli_query($conn, $queryPrice);
$data = array();
while ($row = mysqli_fetch_array($resultPrice)) {
$data[] = $row[0];
}
But instead I want it to choose the last 10 results in Ascending order. I found on other SO questions to use a subquery but every example I try gives no output and no error ??
Tried the below, DOESN'T WORK:
$queryPrice = "SELECT * FROM (SELECT price FROM price_chart ORDER BY id DESC LIMIT 10) ORDER BY id ASC";
$resultPrice = mysqli_query($conn, $queryPrice);
$data = array();
while ($row = mysqli_fetch_array($resultPrice)) {
$data[] = $row[0];
}
I also tried specifying the table name again and using the IN, also doesn't work:
$queryPrice = "SELECT price FROM price_chart IN (SELECT price FROM price_chart ORDER BY id DESC LIMIT 10) ORDER BY id";
$resultPrice = mysqli_query($conn, $queryPrice);
$data = array();
while ($row = mysqli_fetch_array($resultPrice)) {
$data[] = $row[0];
}
In both examples my array is blank instead of returning the last 10 results and there are no errors, so I must be doing the subquery wrong and it is returning 0 rows.
The subquery doesn't select the id column, so you can't order by it in the outer query. Also, MySQL requires that you assign an alias when you use a subquery in a FROM or JOIN clause.
$queryPrice = "SELECT *
FROM (SELECT id, price
FROM price_chart
ORDER BY id DESC LIMIT 10
) x ORDER BY id ASC";
$resultPrice = mysqli_query($conn, $queryPrice) or die (mysqli_error($conn));
$data = array();
while ($row = mysqli_fetch_assoc($resultPrice)) {
$data[] = $row['price'];
}
You would have been notified of these errors if you called mysqli_error() when the query fails.
Your second query is the closest. However you need a table alias. (You would have seen this if you were kicking out errors in your sql. Note you will need to add any field that you wish to order by in your subquery. In this case it is id.
Try this:
SELECT * FROM (SELECT price, id
FROM price_chart ORDER BY id DESC LIMIT 10) as prices
ORDER BY id ASC
You must have errors, because your SQL queries are in fact incorrect.
First, how to tell you have errors:
$resultPrice = mysqli_query (whatever);
if ( !$resultprice ) echo mysqli_error($conn);
Second: subqueries in MySQL need aliases. So you need this:
SELECT * FROM (
SELECT id, price
FROM price_chart
ORDER BY id DESC LIMIT 10
) AS a
ORDER BY id ASC";
See the ) AS a? That's the table alias.
I'm sorting my table which has the id and highscore of the user. This is ordered in descending and I'm passing in the id of the current user to find where he ranks.
I.e: I pass in the ID of the current user and want to echo where he ranks.
select *
from (
select *
from players
order by highscore desc
limit 10
) t
where id = $current_user
I've tried this but no luck with getting the data output in PHP..
$result = $mysqli->query("SELECT COUNT(*) AS rank FROM players WHERE highscore >= (SELECT highscore FROM players WHERE id=$current_user)");
What must I modify to the above to get that users ranking and then echo out his ranking number in PHP? Thanks!
You need to put the data into an array once you query it from the database. Try using mysqli's fetch_assoc like this:
$result = $mysqli->query("SELECT COUNT(*) AS rank FROM players WHERE highscore >= (SELECT highscore FROM players WHERE id=$current_user)");
// Put the data from the query into an array
$row = $result->fetch_assoc();
// Store the rank in a variable named $rank
$rank = $row['rank'];
echo $rank;
ok so i coded in a news section and everytime i insert new news,its shows below the old one.
i want to make it ORDER BY id but make it start like backwards.i dont know how to explain but yeh
i want them to be ordered by the newest added by the id so if the 1st row that was inserted's id is 1 then i want it to show below the next id.
so row with id = 2 will be here
so row with id = 1 will be here
thats how i want it to be, instead of it being like this
so row with id = 1 will be here
so row with id = 2 will be here
.
Sorry for my bad explanation i hope this is understandable
heres my code so far
<?php
require("include/config.php");
$sqlnews = mysql_query("SELECT * FROM news ORDER BY id");
while($row = mysql_fetch_array($sqlnews)) {
$dbdate = $row['date'];
$dbnews = $row['news'];
echo "<h1><strong>$dbdate</strong></h1>";
echo "<div class='content'>$dbnews</div><br><br>";
}
?>
add DESC in your ORDER BY clause
SELECT * FROM news ORDER BY id DESC
by default, it is in ASC mode.
SELECT * FROM news ORDER BY id DESC
DESC is the descending keyword ASC is ascending
If you specify neither then default behaviour is ascending
Just use DESC keyword in your sql query.
$sqlnews = mysql_query("SELECT * FROM news ORDER BY id DESC");
However, it isn't really such a good idea to use id, because semantically, there is nothing preventing somebody from changing the sequence which counts up automatically assigning the ID.
Therefore, you should add a column created_at. Everytime you insert a row, you can use the SQL function NOW().
The advantage is that you can say:
SELECT * FROM news WHERE created_at <= NOW() ORDER BY created_at DESC
This means that you can schedule news items ahead of time, and it will automatically display when the date/time arrives!
$sqlnews = mysql_query("SELECT * FROM news ORDER BY id DESC");
try this:
just have to add
order by id DESC
Just replace your code by this code:
<?php
require("include/config.php");
$sqlnews = mysql_query("SELECT * FROM news ORDER BY id DESC");
while($row = mysql_fetch_array($sqlnews)) {
$dbdate = $row['date'];
$dbnews = $row['news'];
echo "<h1><strong>$dbdate</strong></h1>";
echo "<div class='content'>$dbnews</div><br><br>";
}
?>
So I'm trying to add a little bit of convenience to a CRUD by adding next and previous links to navigate between records in my database.
Here are my queries:
$id=$_GET['id'];
$id = $currentid;
$prevquery= "SELECT * FROM inventory WHERE id < $currentid ORDER BY id DESC LIMIT 1";
$prevresult = mysql_query($prevquery);
$nextquery= "SELECT * FROM inventory WHERE id > $currentid ORDER BY id ASC LIMIT 1";
$nextresult = mysql_query($nextquery);
?>
Here is my HTML:
Previous
Next
Now I tested these queries in PHPMyAdmin and they produced the result I wanted, but I can't get my hyperlinks to actually be supplied with the correct IDs... they're just blank after the =. What am I doing wrong?
mysql_query() returns a result set (resource). To get the actual rows from the result set, you need to use a function like mysql_fetch_row().
Your code for the "next" link would look something like:
PHP
$nextquery= "SELECT * FROM inventory WHERE id > $currentid ORDER BY id ASC LIMIT 1";
$nextresult = mysql_query($nextquery);
if(mysql_num_rows($nextresult) > 0)
{
$nextrow = mysql_fetch_row($nextresult);
$nextid = $nextrow['id'];
}
HTML
Next
and the previous link would be done similarly.
Obligatory note: For new code, you should seriously consider using PDO.
Advanced note:
You could combine your queries into a single query like:
SELECT
(
SELECT id
FROM inventory WHERE id < $currentid ORDER BY id DESC LIMIT 1
) AS previd,
(
SELECT id
FROM inventory WHERE id > $currentid ORDER BY id ASC LIMIT 1
) AS nextid
And then adjust the logic accordingly.
Okay, It took a little bit but I figured it out...
PHP
$prevquery= "SELECT * FROM inventory WHERE id < $currentid ORDER BY id DESC LIMIT 1";
$prevresult = mysql_query($prevquery) or die(mysql_error());
while($prevrow = mysql_fetch_array($prevresult))
{
$previd = $prevrow['id'];
}
$nextquery= "SELECT * FROM inventory WHERE id > $currentid ORDER BY id ASC LIMIT 1";
$nextresult = mysql_query($nextquery) or die(mysql_error());
while($nextrow = mysql_fetch_array($nextresult))
{
$nextid = $nextrow['id'];
}
HTML
Previous
Next
Thanks for the help, I think it put me on the right course. I'll look into that PDO stuff for the future. I'm just now starting to get a hang of the old MYSQL/PHP syntax and now all the sudden there's a new format... tough to keep up with it all!
The resultant code has a culprit at the very beginning and end of the table. Your code will "die" as you ordered. Instead you might check the query results ($prevresult, $nextresult) and decide NOT to show a link for previous or next item.
SELECT
IFNULL(
(SELECT id FROM inventory WHERE id < $currentid ORDER BY id DESC LIMIT 1 ) , (SELECT id FROM inventory ORDER BY id DESC LIMIT 1 )
) AS previd ,
IFNULL(
(SELECT id FROM inventory WHERE id > $currentid ORDER BY id ASC LIMIT 1 ),
(SELECT id FROM inventory ORDER BY id ASC LIMIT 1 )
) AS nextid
I have the selecting from the last ten entries working, but am unsure how to get the most popular from these ten entries? Also how would I count the number of the most popular entry & output it to a percentage?
<?php
$sql = "SELECT data FROM table_answers ORDER BY id DESC LIMIT 10";
$result = mysql_query ($sql, $db);
while ($row = mysql_fetch_array ($result))
{
echo "[".$row['data']."]";
}
?>
And I have tried to do the WHERE value as well but it doesn't return any result.
$sql = "SELECT data FROM table_answers WHERE id IN (SELECT id FROM table_answers
ORDER BY id DESC LIMIT 10) ORDER BY popularity DESC LIMIT 1";
$result = mysql_query ($sql, $db);
while ($row = mysql_fetch_array ($result))
{
echo " [".$row['data']."] ";
}
Anyone have any idea what I might be doing wrong here? please
This should solve the problem -
SELECT tableorder.*
FROM (SELECT *
FROM table
ORDER BY id DESC
LIMIT 10) tableorder
ORDER BY tableorder.popularity DESC
LIMIT 1
The inner query will sort on the basis on id and get the top 10. The outer will again sort the 10 rows on the basis of popularity and return the row with highest popularity.
SELECT data
FROM (
SELECT data
FROM table_answers
ORDER BY id DESC
LIMIT 10
) t
ORDER BY popularity