I am not familiar in this style of coding syntax but I want to use this for my project.
I have a question on how to integrate this query:
SELECT max(id) FROM assignment_billing WHERE assignment_id = 37
into this syntax.
public function fetchBillingByParentId($db,$id) {
$select = $db->select()->from('assignment_billing')->where('assignment_id = '.$id);
$stmt = $select->query();
$result = $stmt->fetchAll();
return $result;
}
I want to use max to get the highest id on that table but my syntax doesn't work.
public function fetchBillingByParentId($db,$id) {
$select = $db->select('max(id)')->from('assignment_billing')->where('assignment_id = '.$id);
$stmt = $select->query();
$result = $stmt->fetchAll();
return $result;
}
Did I forgot something? the first syntax is working though. But in the second syntax it doesn't return any value? I think I have an error in 'select('max(id)')->' line. What might be the proper arrangement in this kind of syntax?
Anytime you use an aggregate you must alias the column.
$select = $db->select('max(id) AS balloon')->from('assignment_billing')->where('assignment_id = '.$id);
You would then reference balloon as the column.
Related
This question already has answers here:
Single result from database using mysqli
(6 answers)
Closed 2 years ago.
I am trying to write a function that will check for a single value in the db using mysqli without having to place it in an array. What else can I do besides what I am already doing here?
function getval($query){
$mysqli = new mysqli();
$mysqli->connect(HOST, USER, PASS, DB);
$result = $mysqli->query($query);
$value = $mysqli->fetch_array;
$mysqli->close();
return $value;
}
How about
$name = $mysqli->query("SELECT name FROM contacts WHERE id = 5")->fetch_object()->name;
The mysql extension could do this using mysql_result, but mysqli has no equivalent function as of today, afaik. It always returns an array.
If I didn't just create the record, I do it this way:
$getID = mysqli_fetch_assoc(mysqli_query($link, "SELECT userID FROM users WHERE something = 'unique'"));
$userID = $getID['userID'];
Or if I did just create the record and the userID column is AI, I do:
$userID = mysqli_insert_id($link);
Always best to create the connection once at the beginning and close at the end. Here's how I would implement your function.
$mysqli = new mysqli();
$mysqli->connect(HOSTNAME, USERNAME, PASSWORD, DATABASE);
$value_1 = get_value($mysqli,"SELECT ID FROM Table1 LIMIT 1");
$value_2 = get_value($mysqli,"SELECT ID FROM Table2 LIMIT 1");
$mysqli->close();
function get_value($mysqli, $sql) {
$result = $mysqli->query($sql);
$value = $result->fetch_array(MYSQLI_NUM);
return is_array($value) ? $value[0] : "";
}
Here's what I ended up with:
function get_col($sql){
global $db;
if(strpos(strtoupper($sql), 'LIMIT') === false) {
$sql .= " LIMIT 1";
}
$query = mysqli_query($db, $sql);
$row = mysqli_fetch_array($query);
return $row[0];
}
This way, if you forget to include LIMIT 1 in your query (we've all done it), the function will append it.
Example usage:
$first_name = get_col("SELECT `first_name` FROM `people` WHERE `id`='123'");
Even this is an old topic, I don't see here pretty simple way I used to use for such assignment:
list($value) = $mysqli->fetch_array;
you can assign directly more variables, not just one and so you can avoid using arrays completely. See the php function list() for details.
This doesn't completely avoid the array but dispenses with it in one line.
function getval($query) {
$mysqli = new mysqli();
$mysqli->connect(HOST, USER, PASS, DB);
return $mysqli->query($query)->fetch_row()[0];
}
First and foremost,
Such a function should support prepared statements
Otherwise it will be horribly insecure.
Also, such a function should never connect on its own, but accept an existing connection variable as a parameter.
Given all the above, only acceptable way to call such a function would be be like
$name = getVal($mysqli, $query, [$param1, $param2]);
allowing $query to contain only placeholders, while the actual data has to be added separately. Any other variant, including all other answers posted here, should never be used.
function getVal($mysqli, $sql, $values = array())
{
$stm = $mysqli->prepare($sql);
if ($values)
{
$types = str_repeat("s", count($values));
$stm->bind_param($types, ...$values);
}
$stm->execute();
$stm->bind_result($ret);
$stm->fetch();
return $ret;
}
Which is used like this
$name = getVal("SELECT name FROM users WHERE id = ?", [$id]);
and it's the only proper and safe way to call such a function, while all other variants lack security and, often, readability.
Try something like this:
$last = $mysqli->query("SELECT max(id) as last FROM table")->fetch_object()->last;
Cheers
i have this function below. that i used to run on a MySQL DB. I had to move to a SQL Server 2008, easy thing.
But, after that, the rowCount() keeps returning -1, I've never had this happen before. I'm sure that my SQL query is returning the results, because if I do a print_r() on my return (the $rows var), everything gets printed.
So, if anyone had this issue, please help me to figure this out.
Sorry for any grammatical mistake.
public function listar(){
$retorno = array();
$sql = "SELECT m.id, m.descricao, m.link, m.categoria, m.icone FROM menus AS m, grupos AS g, permissoes AS p WHERE (g.id = p.idgrupo AND m.id = p.idmenu) AND (p.status = :pstatus AND g.status = :gstatus AND m.status = :mstatus) AND g.id = :gid ORDER BY m.ordem ;";
$vars = array(":pstatus"=>1,":gstatus"=>1,":mstatus"=>1,":gid"=>$_SESSION['group']);
$stmt = $this->pdo->prepare($sql);
foreach($vars as $index => $value){
$stmt->bindValue($index,$value);
}
if($stmt->execute()){
$count = $stmt->rowCount();
$rows = $stmt->fetchAll(PDO::FETCH_OBJ);
$rows['msg'] = '1';
$rows['length'] = $count;
$i = 0;
while($i < $count){
foreach($rows[$i] as $index => $value){
$rows[$i]->$index = utf8_encode($value);
}
$i++;
}
return $rows;
} else {
return array("msg" => '0');
}
}
Got it guys.
The prepare() statement should receive one more parameter. array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL) .
$stmt = $this->pdo->prepare($sql,array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
After that the rowCount() should work fine.
Thanks for the answer #Rasclatt.
I think you may be running into the gotcha on the PDO rowCount() function. As stated in the PHP manual. The second sentence is the gotcha...:
"If the last SQL statement executed by the associated PDOStatement was a SELECT statement, some databases may return the number of rows returned by that statement. However, this behavior is not guaranteed for all databases and should not be relied on for portable applications."
Instead, you should use a COUNT(*) sql statement.
Good evening everyone!
I need your help again. Please bear with me because I am very new to this. Hoping for your understanding. So, I am having a project on oop and pdo. I am having quite hard time converting this into pdo.. Here is my code..
bookReserve.php
while($row=mysql_fetch_array($sql))
{
$oldstock=$row['quantity'];
}
$newstock = $oldstock-$quantity;
Here's what i've done
while($row = $code->fetchAll())
{
$oldstock=$row['quantity'];
}
$newstock = $oldstock-$quantity;
Is that even correct?
And for the oop part, after this while loop I have a query to execute.
$sql="update books set no_copies = '$newstock' where book_title = '$book_title'";
Here's what I've done trying to convert it into pdo
public function bookreserve2($q)
{
$q = "UPDATE books SET quantity WHERE = $newstock where book_title = '$book_title'";
$stmt = $this->con->prepare($q);
$stmt->execute(array(':newstock'=>$newstock));
$result = $stmt->fetch(PDO::FETCH_ASSOC);
return $result;
}
Again, Is that even the correct converted query?
and how would I call $newstock?
P.S. my oop class and pdo is placed in a separate file. Thought this might help.
Thanks
You are not including your query parameters in your function, and your query has syntax errors (extra WHERE) and you are directly inserting your values not using placeholders.
It should look something like -
public function bookreserve2($newstock,$book_title)
{
$q = "UPDATE books SET quantity = :newstock WHERE book_title = :book_title";
$stmt = $this->con->prepare($q);
$stmt->execute(array(':newstock'=>$newstock,':booktitle'=>$book_title));
if($stmt){
return true;
}
else {
return false;
}
}
I'm having some difficulty returning an array out of a while lopp which I have in a function. Here is the code I am using. I am meant to be able to return an array of results from the function which contains the id numbers of pictures associated with a particular user id - in this case I want to print_r the array for the user id of 17. When this code isn't in the function it works, but when I place it in the function, no luck. I presume its related to a mistake I am making in the returning of the array. Your help is greatly appreciated.
function picture($id)
{
$sql = "SELECT * FROM avatar WHERE user_id={$id}";
$result = $database->query($sql);
$results = array();
while ($row = mysql_fetch_assoc($result))
{
$results[] = $row;
}
return $results;
}
$results = picture(17);
print_r($results);
Your function can't access your MySQL link identifier
First of all, you're mixing object-oriented paradigm ($database->query($sql)) with procedural paradigm (mysql_fetch_assoc($result)) which will make your code a nightmare to maintain.
Assuming that $database is a mysql_ link identifier, you'll need to pass it into your function in order to access it there.
function getUserAvatar($database, $id){
$sql = 'SELECT * FROM `avatar` WHERE `user_id`=' . intval($id) . ' LIMIT 1;';
$result = mysql_query($database, $sql);
$row = mysql_fetch_assoc($result);
return $row;
}
$results = picture($database, 17);
Don't just copy-paste that, keep reading!
The above will probably work, but if you're allowing a user to pass that user ID into the function, it's quite possible that they'll be able to find a vulnerability to inject an SQL statement of their choice into your MySQL database.
mysql_ functions are deprecated, so you should ideally stop using them and switch to mysqli or PDO. You'll also want to get an understanding of prepared statements in order to prevent SQL injections. If you can't upgrade, look at the mysql_real_escape_string and intval functions and make sure you sanitize all user inputs before processing them.
The resulting code will look something like this, if you switch to mysqli and prepared statements:
function getUserAvatar($db, $userId) {
$stmt = $db->prepare("SELECT * FROM `avatar` WHERE `user_id`=? LIMIT 1;");
$stmt->bind_param("i", $userId);
$stmt->execute();
$res = $stmt->get_result();
return $res->fetch_assoc();
}
$db = new mysqli("localhost", "user", "password", "database");
$result = getUserAvatar($db, 17);
may be you should try this..
function picture($id)
{
$sql = "SELECT * FROM avatar WHERE user_id={$id}";
$result = $database->query($sql);
$row = mysql_fetch_assoc($result);
return $row;
}
$results = picture(17);
print_r($results);
Basically what I want to do is to use MySqli to just do a query UUID_SHORT() and get the result. No INSERT,UPDATE,DELETE or anything, I just want the value of UUID_SHORT.
Haven't been able to figure it out, any help would be great!
Thanks.
How about SELECT UUID_SHORT();
There is more information in the MySQL documentation.
Example:
function UUID_SHORT(mysqli $db)
{
$result = $db->query("SELECT UUID_SHORT();");
$res = $result->fetch_array();
return $res[0];
}
You can expand function created by #competent_tech to add more flexibility:
Example:
function getUuid(mysqli $db, $short=false)
{
$query = "SELECT " . ($short ? "UUID_SHORT()" : "UUID()");
$result = $db->query($query)->fetch_array();
return $result[0];
}