What's the best, and easiest way to do this? My query currently is:
SELECT *
FROM chat
WHERE (userID = $session AND toID = $friendID)
OR (userID = $friendID AND toID = $session)
ORDER BY id
LIMIT 10
This shows the first 10 rows though, not the last 10.
EDIT: I Want the last 10 rows (Which yes, DESC does this) However I want them to be returned in ASCENDING order.
to reverse the order (therefore get last 10 instead of first 10), use DESC instead of ASC
EDIT
Based on your comment:
SELECT * FROM (
SELECT *
FROM chat
WHERE (userID = $session AND toID = $friendID)
OR (userID = $friendID AND toID = $session)
ORDER BY id DESC
LIMIT 10
) AS `table` ORDER by id ASC
If you want the last 10 then just change ASC to DESC
SELECT *
FROM
chat
WHERE
(userID=$session AND toID=$friendID)
OR
(userID=$friendID AND toID=$session)
ORDER BY id
DESC
LIMIT 10
$con = mysqli_connect("localhost","my_user","my_password","my_db");
$limit = 10;
$query = "SELECT * FROM $table";
$resource = mysqli_query($con,$query);
$total_rows = mysqli_num_rows($resource);
$start = $total_rows-$limit;
$query_limit= $query." LIMIT $start,$limit";
First I have set the limit
$limit = 10;
then
$total_rows = mysqli_num_rows($resource);
Here I have taken total number of rows affected.
$start = $total_rows-$limit;
then substracted limit from number of rows to take starting record number
$query_limit= $query." LIMIT $start,$limit";
and then added limit to the query.
For more information about limit see this link
https://www.w3schools.com/php/php_mysql_select_limit.asp
First select the last 10 from the table, then re-order them in ascending order.
SELECT * FROM (SELECT * FROM table ORDER BY id DESC LIMIT 10) sub ORDER BY id ASC
Related
I want to known how to get last row a value without using while loop for mysql query.
Select data:
$sql = "
SELECT *
FROM status
WHERE author = '$pname'
AND postdate >= '$lsposttime'
ORDER
BY postdate ASC
LIMIT 4";
$query = mysqli_query($conn, $sql);
I want to get 4th row postdate value withoutusing loops.
Not using this:
while ($row = mysqli_fetch_assoc($query)){
}
select *
from status
where author = '$pname'
and postdate >= '$lsposttime'
order by postdate asc LIMIT 3, 1
this will get the fourth row
You can use a query like this:
SELECT *
FROM (
SELECT *
FROM STATUS
WHERE author='$pname'
AND postdate >= '$lsposttime'
ORDER BY postdate ASC LIMIT 4
) tnp
ORDER BY postdate DESC LIMIT 1;
This will return the last row. So if the result only return 2 row it will give the second.
You can use offset in mysql for fetch data from exact place an order.
For your Requirement your query will looks like:
$sql = "
SELECT *
FROM status
WHERE author = '$pname'
AND postdate >= '$lsposttime'
ORDER
BY postdate ASC
LIMIT 1 OFFSET 4";
$query = mysqli_query($conn, $sql);
And for more use of offset you can discover from here
I have this line:
$query = mysql_query("SELECT * FROM livechat WHERE type='public' ORDER BY id ASC LIMIT 15") ;
And this is for chat, however ASC takes only first ID comments, so it shows only 15 old comments (id1, id2 and so on). If I use DESC instead of ASC, it shows new comments, but in a bad way - newest at the top, since this is a chat, newest comments must be at the bottom.
Try creating a temporary table that contains the last 15 results, and then ordering from that table.
select * from (
select * from livechat where type='public' order by id desc limit 15
) tmp order by tmp.id asc
try like this:
$query = mysql_query("SELECT *
FROM (
SELECT *
FROM livechat
WHERE type='public'
ORDER BY id DESC LIMIT 15
) t
order by t.id") ;
I'm just starting with MySQL so I would like to know how can I select only 5 random rows in the last 50 entries of my database? I hope you understand my question.
I'm using PDO and what I have now is this:
$otherChoiseRig = $bdd->query("SELECT * FROM articulos WHERE cat = '$ArtCat' ORDER BY RAND() ");
$otherChoiseRig2 = $otherChoiseRig->fetchAll(PDO::FETCH_ASSOC);
Then I use a PHP foreach loop...
Thank you
The challenge is determining the last 50 entries. Assuming you have an auto-incremented id, you can do:
SELECT a.*
FROM (SELECT a.*
FROM articulos a
WHERE cat = '$ArtCat'
ORDER BY id DESC
LIMIT 50
) a
ORDER BY RAND()
LIMIT 5;
The key idea is the subquery to get the last 50 entries, and then the final query to get the 5 random rows. The subquery needs to specify how you identify the last 50.
$otherChoiseRig = $bdd->query("SELECT * FROM articulos WHERE cat = '$ArtCat' ORDER BY RAND() LIMIT 5 ");
$otherChoiseRig2 = $otherChoiseRig->fetchAll(PDO::FETCH_ASSOC);
just add limit
i assume in your table you have some date column so we can get last 50
SELECT * FROM (SELECT * FROM articulos WHERE cat = '$ArtCat' ORDER BY created_tiem desc limit 50 ) t order by RAND() limit 5;
I tried something like this:
$changed = mysql_query("SELECT * FROM games WHERE changed = 'y' AND human = '$_GET[human]' ORDER BY id DESC LIMIT 100", $link);
$num_rowsc = mysql_num_rows($changed);
So what i want is to select last 100 where human = yes and count where changed = y ..
so get last 100 humans and count how many of them have on changed yes
Are you looking for something like this :
$stmt = $pdo->prepare("SELECT COUNT(*) AS cnt FROM ( SELECT * FROM games
WHERE human= :human ORDER BY id DESC LIMIT 100
) WHERE changed = 'y' ");
$stmt->bindParam(':human', $_GET[human]);
$stmt->execute();
Maybe with this query?
SELECT COUNT(*) AS cnt FROM (
SELECT * FROM games
WHERE human = '".mysql_real_escape_string($_GET[human])."'
ORDER BY id DESC LIMIT 100
) tmp WHERE changed = 'y'
1) try using this as your query:
SELECT count(*) FROM (SELECT * FROM games WHERE changed = 'y' ORDER BY id DESC LIMIT 100) WHERE human = '$_GET[human]'
2) use mysqli
select count(*) as cnt from (
SELECT human FROM games WHERE human = '$_GET[human]' ORDER BY id DESC LIMIT 100
) as changes WHERE changed = 'y'
I'm trying to keep the 10 most recent entries in my database and delete the older ones. I tried DELETE FROM people ORDER BY id DESC LIMIT $excess, but it just deleted the top 10 entries.
$query = "SELECT * FROM people";
$result = mysqli_query($conn, $query);
$count = mysqli_num_rows($result);
if ($count > 10) {
$excess = $count - 10;
$query = "DELETE FROM people WHERE id IN(SELECT id FROM people ORDER BY id DESC LIMIT '$excess')";
mysqli_query($conn, $query);
}
You can use this:-
DELETE FROM `people`
WHERE id NOT IN (
SELECT id
FROM (
SELECT id
FROM `people`
ORDER BY id DESC
LIMIT 10
)
);
Also your query is logically incorrect and you are fetching the records in descending order. i.e. Latest to older and you are deleting the most recent records. Use ASC instead.
Something like this? Gets the ten latest ids in the subquery, then deletes all of the other ids.
DELETE FROM people WHERE id NOT IN (SELECT id FROM PEOPLE ORDER BY id DESC LIMIT 10)
Your logic is all over the place, [you should ORDER BY ASC, not DESC] and your query will take ages if there are [for example] 10,000 entries because you'll have an IN clause with 9,990 entries to compare all 10,000 to.
Select the 10 most recent, and delete where NOT in.
DELETE FROM people
WHERE id NOT IN(
SELECT id
FROM people
ORDER BY id DESC
LIMIT 10
)
Maybe find the ID of the 10th element and then delete all rows which are older?