If I use this in PHP to count records, it gives a count of 1 when there are, in fact, no records. However, when I run the same query in HeidiSQL, phpmyadmin or any other, it gives the proper 0. Why the discrepancy?
if ($result = $mysqli->query($Query)) :
return $result->num_rows;
$MySQLError = ($mysqli->connect_errno) ? mysqli_error($mysqli) : "";
$result->close();
$mysqli->close();
if ($MySQLError) return $MySQLError;
endif;
$Query, in this case, contains:
SELECT COUNT(ID) AS UpdateCount
FROM tablename
WHERE ShowPage = 1 AND
DateUpdated BETWEEN 1554345942 AND 1554950742
While working on something else, the answer to this problem suddenly hit me and it's obvious now that I see it. I was using COUNT(ID) in the query but also using $result->num_rows in the programming. Simply removing the COUNT(ID) did the trick.
SELECT ID
FROM tablename
WHERE ShowPage = 1 AND
DateUpdated BETWEEN 1554345942 AND 1554950742
This issue might occur if another database session has not yet been committed. Making sure that there are no other database sessions which have not been committed solves this problem.
Related
I'm a beginner who has problems with PHP :(
I have a PHP function which shows all the rows from the database table. Now I have to create paging to show only limited number of rows per one page.
I have a problem with retrieving a COUNT result from query. I want to create a condition where PHP & MySQL use LIMIT if number of rows is bigger than needed on one page. The following code:
$count = "SELECT COUNT(*) FROM articles";
$countq = $db->query($count);
$countrs = mysql_fetch_array($countq);
echo $countrs;
should display a number of rows. However, it does not. What am I doing wrong? I want to see a result to make sure that everything else will work fine. But I can't get it working.
Error: mysql_fetch_array() expects parameter 1 to be resource, object given
$db contains database connection information (server, user...) and is working
Use PDO for MySQL query.
$db = new PDO('mysql:host=#YOUR HOST#;dbname=#YOUR DB#;charset=utf8', '#YOUR LOGIN#', '#YOUR PASSWORD#');
$query = $db->query('SELECT COUNT(*) AS count FROM articles');
$countq = $query->fetch();
$query->closeCursor();
echo $countq['count'];
I hope this will help you
You will have to set the limit in the query like
$count = "SELECT COUNT(*) FROM articles LIMIT 5,10";
where 5 is the starting point and 10 is the total number of results you want.
You mention: $db but not what $db is? i mean is it a database object class? this will work directly if you are using the a database class, and if that's the case the class will also have functions which will allow you to query data without using mysql_fetch_array (actually mysqli_fetch_array).
I am using a customized version of DGNews (now defunct) script in my site. In that script, there is a simple method to count the number of hits:
$queryfull = "SELECT * FROM news_publish WHERE id='$newsid'";
$qryfull = #mysql_query($queryfull,$connect) or die ("Wrong Query");
$rowfull = mysql_fetch_array ($qryfull);
$c=$rowfull[click];
$c++;
$d=$c;
#mysql_query("update news_publish set click='$d' where id=$newsid");
I know this script is using outdated mysql query methods, and I am currently not in a position to do a complete upgrade.
But my problem is, 'click' (int) field in all the rows of database, resets to 1 once in a while. I can't figureot how it happens. It happens only once in a year or so. Is this a result of some kind of attempted mysql injection or something? can somebody figureout what is going on here?
thank you
UPDATE
It resets the said field on ALL the rows, not in a single row
$queryfull = "SELECT * FROM news_publish WHERE id='$newsid'";
$qryfull = #mysql_query($queryfull,$connect) or die ("Wrong Query");
$rowfull = mysql_fetch_array ($qryfull);
$c=$rowfull['click'];
$d=$c++;
#mysql_query("update news_publish set click='$d' where id=$newsid");
But you can run only update query as suggested Barmar in comments
#mysql_query("update news_publish set click=click+1 where id=$newsid");
And thats All
I can't exactly know where the overflow is happening but this will help you.
alter news_publish modify click bigint
bigint is much much greater than int.
So, I had this code working earlier today--and all of a sudden it decided to only start displaying the first result from the query. I cannot figure out what i've changed since then, I actually believe that I haven't changed anything... anyway... I've gone into the DB and altered the table so that all the "upgrades" meet the requirements to be displayed, and yet still only one result is being shown.
$sql = "SELECT id, name, cost, count(*) FROM upgrades
WHERE id NOT IN (Select upgrade_id FROM thehave8_site1.user_upgrades WHERE uid = :uid)
AND nullif NOT IN(SELECT upgrade_id FROM thehave8_site1.user_upgrades WHERE uid = :uid2)
AND prereq IN (SELECT upgrade_id FROM thehave8_site1.user_upgrades WHERE uid = :uid3)
;";
$que = $this->db->prepare($sql);
#$que->bindParam(':id', $id); //note the : before id
#$que->bindParam(':id2', $id);
$que->bindParam(':uid', $this->uid);
$que->bindParam(':uid2', $this->uid);
$que->bindParam(':uid3', $this->uid);
try {
$que->execute();
while($row = $que->fetch(PDO::FETCH_BOTH))
{
echo "<div class='upgrade' id={$row[0]}><p>{$row[1]}</p><p>{$row[2]}</p></div>";
}
} catch(PDOException $e) { echo $e->getMessage();}
Problem has been solved, though I'm not sure of the exact reason why, the count(*) being at the end of the query string was preventing the entire code from running properly
Aren't you missing some line of code that advances the result in the query to the next row? When I do loops through recordsets (slightly different than what you are doing but probably not much different) there is usually a MoveNext or something like that - I see nothing like that here.
I don't know this language you are using.
......
I am not being allowed to add a comment to your response so I will add it here..
....
Cool. You really looked like you knew what you were doing, far more advanced than anything I've written! New here also and didn't catch onto the tag system, thanks for pointing that out so I don't need to embarrass myself in future. Glad you've solved it. I think Count (*) would work if you included it as a subquery
SELECT FIELD1, FIELD2, (SELECT count (*) FROM ... ) AS FIELD3
FROM (ETC)
or if you just want its value in the recordset result, compute it ahead of time via query, and then include its value as a dummy/constant field in your select statement. Depending on the query plan in your query engine this may or may not be more efficient.
Or just wait to get Recordcount from your recordset.
I have just started to convert to mysqli due to the added security benefits. The main reason for converting to mysqli was the mysqli_multi_query function though. I had several long, complicated query's with a lot of JOINS in and when I found out about this function I thought I could make it simpler by breaking everything down into separate queries.
However, I have been unable to get the query to work as I want it to and the PHP manual isn't helping me.
Here's what I have so far;
$qry = "SELECT T.T_ID, T.name, T.pic, T.timestamp AS T_ts,
(SELECT COUNT(*) FROM track_plays WHERE T_ID = T.T_ID) AS plays,
(SELECT COUNT(*) FROM track_downloads WHERE T.T_ID = T_ID) AS downloads
FROM tracks T WHERE ID = '$ID';
";
$qry .= "SELECT S_ID, status, timestamp AS S_ts FROM status WHERE ID = '$ID';";
$qry .= "SELECT G_ID, gig_name, date_time, lineup, price, ticket, venue, G_pic, timestamp AS G_ts FROM gigs WHERE ID = '$ID'";
// Execute multi query
if (mysqli_multi_query($con,$qry)){
do {
// Store first result set
if ($result=mysqli_store_result($con)){
while ($row=mysqli_fetch_array($result)){
print_r($row);
}
}
}
while (mysqli_next_result($con));
}
This works fine and the array is printed as expected. However, i want to set a lot of variables for use later on. I won't list all of the variables but I have a few like this;
$S_ID = htmlspecialchars($row['S_ID']);
$T_ID = htmlspecialchars($row['T_ID']);
$G_ID = htmlspecialchars($row['G_ID']);
The variables are retrieved but due to the loop nature of the function PHP errors are given as well saying the $S_ID or $G_ID are undefined. $T_ID does not get an undefined error as it is the first query as is not looped over.
If you need any more information or I have not explained well enough just ask!
A while back ago i have had the same issues, and also for the same reason i have migrated from mysql to mysqli.
Sadly, it wasnt the best sollution for many cases, as i have realized on the way.
While implementing stuff with mysqli and multi query i still have had some issues that i had with mysql.
The solution i recommend, is to use views on your complicated querys.
it makes your coding and querys far less complicated.
I know it is not the answer you have been looking for, but give it a thought.
So far, every time I use a mysqli_multi_query, my do-while condition is:
while(mysqli_more_results($connection) && mysqli_next_result($connection));
You may like to replace your while statement and see if that helps.
If not, are you differentiating between each subsequent query when you are assigning these $S_ID, $G_ID variables? Are you inadvertently overwriting a variable with an empty $row[] value?
I also didn't see mysqli_free_result($result) in your code.
I'll even offer some error checking as a garnish.
preg_match_all("/(?:SELECT\s(.*?),\s.*?(?:;|$))/",$qry,$first_columnname);
if (mysqli_multi_query($con,$qry)){
do {
if ($result=mysqli_store_result($con)){
$query_identifier=array_shift($first_columnname[1]);
while ($row=mysqli_fetch_array($result)){
if($query_identifier)=="T.T_ID"){
//do something...
}elseif($query_identifier)=="S_ID"){
//do something...
}elseif($query_identifier)=="G_ID"){
//do something...
}
}
mysqli_free_result($result);
}
}
while(mysqli_more_results($con) && mysqli_next_result($con));
}
if($error_mess=mysqli_error($con)){echo "Error = $error_mess";}
Let me know if any of these small changes do the trick.
I'm having problems debugging a failing mysql 5.1 insert under PHP 5.3.4. I can't seem to see anything in the mysql error log or php error logs.
Based on a Yahoo presentation on efficient pagination, I was adding order numbers to posters on my site (order rank, not order sales).
I wrote a quick test app and asked it to create the order numbers on one category. There are 32,233 rows in that category and each and very time I run it I get 23,304 rows updated. Each and every time. I've increased memory usage, I've put ini setting in the script, I've run it from the PHP CLI and PHP-FPM. Each time it doesn't get past 23,304 rows updated.
Here's my script, which I've added massive timeouts to.
include 'common.inc'; //database connection stuff
ini_set("memory_limit","300M");
ini_set("max_execution_time","3600");
ini_set('mysql.connect_timeout','3600');
ini_set('mysql.trace_mode','On');
ini_set('max_input_time','3600');
$sql1="SELECT apcatnum FROM poster_categories_inno LIMIT 1";
$result1 = mysql_query($sql1);
while ($cats = mysql_fetch_array ($result1)) {
$sql2="SELECT poster_data_inno.apnumber,poster_data_inno.aptitle FROM poster_prodcat_inno, poster_data_inno WHERE poster_prodcat_inno.apcatnum ='$cats[apcatnum]' AND poster_data_inno.apnumber = poster_prodcat_inno.apnumber ORDER BY aptitle ASC";
$result2 = mysql_query($sql2);
$ordernum=1;
while ($order = mysql_fetch_array ($result2)) {
$sql3="UPDATE poster_prodcat_inno SET catorder='$ordernum' WHERE apnumber='$order[apnumber]' AND apcatnum='$cats[apcatnum]'";
$result3 = mysql_query($sql3);
$ordernum++;
} // end of 2nd while
}
I'm at a head-scratching loss. Just did a test on a smaller category and only 13,199 out of 17,662 rows were updated. For the two experiments only 72-74% of the rows are getting updated.
I'd say your problem lies with your 2nd query. Have you done an EXPLAIN on it? Because of the ORDER BY clause a filesort will be required. If you don't have appropriate indices that can slow things down further. Try this syntax and sub in a valid integer for your apcatnum variable during testing.
SELECT d.apnumber, d.aptitle
FROM poster_prodcat_inno p JOIN poster_data_inno d
ON poster_data_inno.apnumber = poster_prodcat_inno.apnumber
WHERE p.apcatnum ='{$cats['apcatnum']}'
ORDER BY aptitle ASC;
Secondly, since catorder is just an integer version of the combination of apcatnum and aptitle, it's a denormalization for convenience sake. This isn't necessarily bad, but it does mean that you have to update it every time you add a new title or category. Perhaps it might be better to partition your poster_prodcat_inno table by apcatnum and just do the JOIN with poster_data_inno when you need the actually need the catorder.
Please escape your query input, even if it does come from your own database (quotes and other characters will get you every time). Your SQL statement is incorrect because you're not using the variables correctly, please use hints, such as:
while ($order = mysql_fetch_array($result2)) {
$order = array_filter($order, 'mysql_real_escape_string');
$sql3 = "UPDATE poster_prodcat_inno SET catorder='$ordernum' WHERE apnumber='{$order['apnumber']}' AND apcatnum='{$cats['apcatnum']}'";
}