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
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.
I have a user form that sets a single record "current". No more than one record can be set to current at a time. So, I present the user a single drop down list, they choose the item they want to set current and hit "UPDATE" at the bottom of the form.
The PHP/Mysqli needs to go in and set all records column "current" to a value of 0 then update the one from the form to a value of "1".
Initially, I just did a simple count the number of rows, and run a bunch of queries to update the column to 0 or 1 if the loop counter = the id of the row. Well... that broke quick as I started doing testing on other portions and the index numbers got higher than the total number of rows. Yes, dumb way to do it initially!
Here's what I tried to do with the PHP / MySQL code:
// $link is the database link defined elsewhere. This does work as I use it all over the place
$setCurrent = X; // This is the number passed from my form
$init_query = "SELECT id, current FROM myTable";
if ($stmt = $link->$prepare($init_query) {
$stmt->execute() or die ($stmt->error);
$stmt ->bind_result($id, $current)
while ($stmt->fetch()){
if ($id == $setCurrent){
$update_sql = "UPDATE myTable SET current ='1' WHERE id='".$setCurrent."'";
$stmt2 = $link->prepare($update_sql);
$stmt2->execute;
}
else {
$update_sql = "UPDATE myTable SET current ='0' WHERE id='".$id."'";
$stmt2 = $link->prepare($update_sql);
$stmt2->execute;
}
$stmt->close();
This fails and gives me a Fatal error: Uncaught Error: Call to a member function execute on boolean in .....
I am racking my brain over this and can't figure out what the heck is going on. Its been a few years since I have worked in PHP/MySql and this is my first forray into OO Mysqli. Please be gentle :)
You're missing two closing curly braces. One for the first if() and the other for while()
why do them one at a time? You can do it in one query
$setCurrent = X;
$query = 'UPDATE myTable
SET `current` = (id = :current)';
$stmt = $link->prepare($query);
$stmt->bindValue(':current', $setCurrent);
$stmt->execute();
(and misusing the fact that if id equals $setCurrent, the part between ( ) resolves to true, which is 1.)
some explaining:
SELECT 10=10; would give a kind of "TRUE". But as Mysql does not give true, it give 1.
the same goes for:
SELECT 10=20; This is FALSE, so gives you 0.
Now back to your query: you want to get a value 0 for all record for which id not equal to some-number. And you want 1 when equal:
So you have to compare the column id's value to $setCurrent. When they match you get 1 and you put that 1 into the column "current"
And when they don't match, all other cases, then you get a 0 and that 0 goes into the column Current.
And yes, this could also be done as:
UPDATE mytable
SET `current` = CASE id
WHEN $setCurrent THEN 1
ELSE 0
END CASE
or using IF,
But they other syntax is way shorter
edit
backtics are needed around column name, as current is a reserved word
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.
So I have the following mysql statement saving to an array:
$sql = "SELECT did FROM did WHERE id = '$did_id'";
$result = mysqli_query($link, $sql, MYSQLI_STORE_RESULT);
while($row = $result->fetch_row()){
$did[] = $row;
}
That part works great. But now I need to take the values in the $did array and perform another lookup using the values in it. The way it works is we have users assigned to certain did's. So I find the did's that the user is assigned to (the $did array) and only show them results from another table based on those did values. I have no idea how this part works, but this is what my next statement needs to do:
SELECT * FROM log WHERE did_id = "the values in $did array"
Hope someone can help. I really appreciate it. I haven't really been able to find anything on it.
You can use php's join with mysql's IN to make comma separated strings you can also use implode , join() is an alias of implode();
SELECT * FROM log WHERE did_id IN( ".join(',',$did).")
One thing to mention here that your $did should contains ids in manner like
array("1","2","3"....)
So in your loop fetch first index that holds did column value
$did[] = $row[0];
Note: i assume did , did_id type is int or bigint
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.