I want to select all records from my table and loop through all those records until I get to the record where the numtimespaid column is equal to 0. Once I find that column I want to update it to 2 for that record and then exit out. Here is what I have that is not working correctly:
$query1 = "SELECT * FROM ".$line." ORDER BY datestamp, timestamp";
$result1 = mysql_query($query1) or die(mysql_error());
while($row = mysql_fetch_array($result1)){
if ($row[numtimespaid] == 0) {
$queryupdate="UPDATE ".$line." SET numtimespaid=1";
$resultu=mysql_query($queryupdate);
break;
}
}
Any ideas as to what I'm doing wrong and/or the right way of doing this?
There is no need whatsoever to loop over rowset from a SELECT statement. You can simply update the first row with that value. This query will update exactly one record matching numtimespaid = 0. If you want to update all rows matching that criterion, just remove the LIMIT 1.
$result = mysql_query("UPDATE $line SET numtimespaid=1 WHERE numtimespaid = 0 ORDER BY datestamp, timestamp LIMIT 1");
By the way, we don't know what the contents of $line are, but hopefully you have properly filtered that value if it comes from user input. If it does comes from user input, it's recommended to check its value against a whitelist of possible table names:
// $line can be one of table1,table2,table3
if (!in_array($line, array('table1','table2','table3')) {
// FAIL, don't execute the query
}
if ($row[numtimespaid] == 0) {
Generally gets interpreted as numtimespaid being an undefined constant. Put quotes around it, like this:
if ($row['numtimespaid'] == 0) {
Then, realize Michael's answer is just better overall.
Related
$sql = "SELECT firstname FROM candidate_info1 WHERE votes=(select MAX(votes) from candidate_info1";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// how do i echo the firstname of candidate with highest votes??
}
I'm new to PHP so please be gentle.
Here in the code I have to return the name of the person with maximum number of votes(stored in database candidate_info1), how do I do that?
What am I doing wrong?
Your query seems to be correct, since it:
returns the firstname
of the correct table
for the record(s) which match in vote number to the maximum vote number
However, if you need a single value, then you can use an order by desc, as suggested in other answers. If you want to return the firstname of all the records having the same vote number as the maximum, then order by desc is inadequate here.
Also, if your problem is that votes is not stored in this table, but rather in a different table, then you might need to find the groups having the maximum count from there, selecting the foreign key and then return the values in your main query using the in operator. Anyway, if you have a specific problem which was not mentioned here, then you will need to add the details.
You have to fetch record By
$person_name = $result->fetch_assoc($result);
$person_name = $person_name['firstname ']
while($row = $result->fetch_assoc()) {
$firstname=$row['firstname'];
}
echo $firstname;
In your query, you already return the name with the max votes so you just have to fetch the results in order to show that name.
On my XAMPP server I have a database table on phpMyAdmin. In that table, I have a few columns, and one of them is id column (Integer).
I want to get the latest added item's ID, increment it by one and then assign it to a new item that the function adds to the table.
The problem is that whenever there is a new item, it is automatically assigned with 1 as id, nothing above 1.
$sql = "SELECT * FROM items";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// output data of each row
while ($row = $result->fetch_assoc()) {
if( $_SESSION["increment"] == "yes"){
$_SESSION["id"] = $row["id"];
}else
$_SESSION["id"]=$_SESSION["id"]+1;
}
} else {
$_SESSION["id"] = 1;
}
This will give you last increment Id.
$sql = "SELECT id FROM items order by id DESC LIMIT 0,1";
Then you dont want have a while loop to find last increment Id.
error reporting said what? and mysqli_error($conn)?
-- Fred-ii-
The above request by Fred -ii- sums it up, if your ->num_rows is returning zero or not a number (false) then you have an SQL error, so you need to check your error logs, and check your database connection.
Have you started your session with session_start?
Do you intend that the first else calls without brackets, only executing the single following line, $_SESSION["id"]=$_SESSION["id"]+1; ?
It seems to me that you need well known AUTO_INCREMENT functionality built inside MySQL database. Just define in your database schema for your table that column is AUTO_INCREMENT column type, and it will be automatically incremented by 1 upon each new insert into table.
$unique = array();
$sql = "SELECT ID, TitleName, ArtistDisplayName, Mix FROM values_to_insert as A
WHERE A.ID = ";
//Get a single row from our data that needs to be inserted...
while($result = $conn->query(($sql. $count)))
{
//Get the $data of the single row query for inserting.
$data = mysqli_fetch_row($result);
$count++;
//SQL to get a match of the single row of $data we just fetched...
$get_match = "SELECT TitleName_ti, Artist_ti, RemixName_ti from titles as B
Where B.TitleName_ti = '$data[1]'
and B.Artist_ti = '$data[2]'
and B.RemixName_ti = '$data[3]'
LIMIT 1";
//If this query returns a match, then push this data to our $unique value array.
if(!$result = $conn->query($get_match))
{
//If this data has been pushed already, (since our data includes repeats), then don't
//put a repeat of the data into our unique array. Else, push the data.
if(!in_array($unique, $data))
{
echo 'Pushed to array: ' . $data[0] . "---" . $data[1] . "</br>";
array_push($unique, $data);
}
else
echo'Nothing pushed... </br>';
}
}
This has taken 5+ minutes and nothing has even printed to screen. I'm curious as to what is eating up so much time and possibly an alternative method or function for whatever it is taking all this time up. I guess some pointers in the right direction would be great.
This code basically gets all rows, one at a time, of table 'A'. Checks if there is a match in table 'B', and if there is, then I don't want that $data, but if there isn't, I then check whether or not the data itself is a repeat because my table 'A' has some repeat values.
Table A has 60,000 rows
Table B has 200,000 rows
Queries within queries are rarely a good idea
But there appear to be multiple issues with your script. It might be easier to just do the whole lot in SQL and push the results to the array each time. SQL can remove the duplicates:-
<?php
$unique = array();
$sql = "SELECT DISTINCT A.ID,
A.TitleName,
A.ArtistDisplayName,
A.Mix
FROM values_to_insert as A
LEFT OUTER JOIN titles as B
ON B.TitleName_ti = A.ID
and B.Artist_ti = A.TitleName
and B.RemixName_ti = A.ArtistDisplayName
WHERE B.TitleName_ti IS NULL
ORDER BY a.ID";
if($result = $conn->query(($sql)))
{
//Get the $data of the single row query for inserting.
while($data = mysqli_fetch_row($result))
{
array_push($unique, $data);
}
}
As to your original query.
You have a count (I presume it is initialised to 0, but if a character then that will do odd things), and get the records with that value. If the first id was 1,000,000,000 then you have done 1b queries before you ever find a record to process. You can just get all the rows in ID order anyway by removing the WHERE clause and ordering by ID.
You then just get a single record from a 2nd query where the details match, but only process them if no record is found. You do not use any of the values that are returned. You can do this by doing a LEFT OUTER JOIN to get matches, and checking that there was no match in the WHERE clause.
EDIT - as you have pointed out, the fields you appear to be using to match the records do not appear to logically match. I have used them as you did but I expect you really want to match B.TitleName_ti to A.TitleName, B.Artist_ti to A.ArtistDisplayName and B.RemixName_ti to A.Mix
Just a little assistance, This is a pretty simple problem but it doesn't seem to work right. I am just comparing the value in a variable with all the values in a sql column. Same as if I were to compare a username input to the list of usernames in a sql column. This however is just to compare that the item id being stored in the column for that row is not an item id that is already in use.
I tested the value that I am getting back from the sql query and it is equal to the item id I typed in the input. What you will see below is the actual test to see if the id I am getting back is the one that I am looking for as well as the id of the row I can find that value in. The results I get is
2, 000002 (which is correct) that is what I am looking for.
$itemId = $_POST['itemId'];
if($sqlItemId = $dbCon->query("SELECT * FROM CVCinStoreCoins WHERE itemId = '$itemId'")){
while($data = $sqlItemId->fetch_assoc()){
printf("<p>%s, %s</p>", $data['id'], $data['itemId']);
die();
}
Then I took this out and tried to compare the value in the variable which is the same itemId already stored (000002). that is where I am going wrong.
I modified the code to look like this for further testing. Seems straight forward yet i am getting a FALSE response providing the latter echo statement "Item Id is not in use" But it is in the DB. I tried it a few different ways based on what I read in stackoverflow but none are giving me the right answer.
$sqlItemId = $dbCon->query("SELECT * FROM CVCinStoreCoins WHERE itemId = '$itemId'");
if($itemId == $sqlItemId){
echo "This item id is already in use. \n";
die();
} else {
echo "Item Id is not in use:";
die();
}
At one point I even tried a while statement to fetch the associated values prior to testing it but that didn't turn up a positive result either. Any suggestions?
Inside $sqlItemId you have the full table row (if any), not only its ID; change the SQL into a count and check the number of rows returned (if greater than 0 you have a duplicate):
$rowsCount = $dbCon->query("
SELECT COUNT(*)
FROM CVCinStoreCoins
WHERE itemId = '$itemId'
");
I don't know what $dbCon is (Doctrine DBAL? mysqli?) so I can't tell you how to use query's result.
Wy don't you just count it,
$result = $dbCon->query("SELECT COUNT(itemId) FROM CVCinStoreCoins WHERE itemId = $itemId");
if $result > 0
What is the right way of checking if the required data is in the database?
What I use currently is,
mysql_query("SELECT anyfield FROM table WHERE field='$data'");
and then check the if any rows are affected.
But I dont really have any use with the extracted data anyfield.
Eventhough the resource usage is so minor here, what is the right way to check if data exists in a db without extracting any other fields from the table?
Let the database count and retrieve the count data from the query.
$result = mysql_query('SELECT COUNT(*) FROM `table` WHERE `field` = ...');
if (!$result) {
die(mysql_error());
}
if (mysql_result($result, 0, 0) > 0) {
// some data matched
} else {
// no data matched
}
$result = mysql_query("SELECT `field` FROM `table` WHERE `field` = '".$data."'");
if (mysql_num_rows($result)){
// Rows exist
}
OR
$result = mysql_query("SELECT COUNT(`field`) as count FROM `table` WHERE `field` = '".$data."'");
$row = mysql_fetch_array($result);
if ($row ['count']){
// Rows exist
}
I would ensure, if I was checking for data, that as little data was returned as possible.
Fetch one field (I usually do id) and ensure you use LIMIT, eg. LIMIT 1... assuming you only want to know if any record exists.
Because you're using a PHP variable to find a record, if it suits your situation, you could perhaps do a LEFT JOIN on the first SQL line that gets $data, but that might just as easily be overkill for what you need.