PHP PDO count and sum value from MySQL table - php

Well, I'm pretty sure this is just a novice question, so please forgive me for that, but I feel like I'm losing my mind.
I have a simple MySQL rating table and I need to count rows and to sum rates values (int) with PHP PDO
$sql = "SELECT rate FROM rating_table";
$query = $db->query($sql);
$rate_times = count($query->fetchAll()); // it works!
echo '<p>'.$rate_times.'</p>';
$sum_rates = array_sum($query->fetchAll()); // it doesn't work!
echo '<p>'.$sum_rates.'</p>';
Thank you in advance for any suggestion

If I understand you right, all you have to do is to modify your sql request, this will return a single row
sql = "SELECT sum(rate) as rate_sum, count(*) as record_count FROM rating_table";
$query = $db->query($sql);
$row = $query->fetch(PDO::FETCH_ASSOC);
if ($row) {
$sum = $row['rate_sum'];
$count = $row['record_count'];
}

Related

How to display field from MySQL?

I'm trying to display a field from my MySQL database. It's in the table tblproducts in the row with the id is set to 1. And under the column qty.
This is the code I'm using:
<?php
mysql_connect("localhost","username","password");
mysql_select_db("database_name");
$available = "SELECT qty FROM tblproducts WHERE id = 1";
$result = mysql_query($available);
echo $result;
?>
However, I keep getting this message: Resource id #2
I've done a bit of research and seen where other people are having similar problems but most of them are trying to display their data in an HTML table whereas I just need the data from 'qty' to display. And of course I'm definitely not a MySQL guru.
Can anyone help me out with this please?
Try changing this:
$result = mysql_query($available);
To this:
$result = mysql_result(mysql_query($available), 0);
Let's start from the start. (I'll assume you have the connection set)
Form the query
$query = "SELECT `qty`
FROM `tblproducts`
WHERE `id` = 1";
Execute the query
$run = mysql_query($query);
Now, put the result in an assoc array
$r = mysql_fetch_array($run);
See the contents of the array
echo $r['qty'];
It's also advised that you move up from mysql to either mysqli, or PDO. PDO is preferred as you're not bound to the MySQL database model.
Try this:
Here you need to generate associative array and then get the resulting row.
$query = "SELECT `qty` FROM `tblproducts` WHERE `id` = 1";
$run = mysql_query($query);
$r = mysql_fetch_array($run);
echo $r['qty'];
-
Thanks

PHP Zend - Execute to get a rowset and total number of records

I encounter some problem where i want to execute a SQL statement and get the total number of records + all the records.
$strSQL = "SELECT * FROM table WHERE ProjectID = 1 ";
$stmt = $db->query($strSQL);
$total = count($stmt->fetchAll());
while ($row = $stmt->fetch()){
..No More Record Shown here..
}
but there is no more record in the while loop after i execute fetchAll, i believe I need to get back to the first row or something, anyone know how to fix this?
You've already fetched all the records with fetchAll(). So when you call fetch(), there are no more records to read. Try storing the return value of fetchAll() in a variable and iterating through that. Something like this:
$strSQL = "SELECT * FROM table WHERE ProjectID = 1";
$stmt = $db->query($strSQL);
$allRows = $stmt->fetchAll();
$total = count($allRows);
foreach ($allRows as $row){
// process each $row
}

Question if my code is a low resources one

Hi please tell me if this is a low resources piece of code, and if it is not how shall I change it ? Thank you!
$query = 'SELECT MAX(ID) as maxidpost
FROM wp_posts';
$result = mysql_query($query) or die(mysql_error());
while($row = mysql_fetch_array($result)) {
$postid = $row['maxidpost']+1;
echo "p=$postid";
The improvement is debatable, but:
$query = 'SELECT MAX(ID) +1 as maxidpost
FROM wp_posts';
$result = mysql_query($query) or die(mysql_error());
while($row = mysql_fetch_array($result)) {
echo "p = ". $row["maxidpost"];
You can do math in SQL statements, saving you from having to do the operation in PHP.
It'd be nice to know what you're using this for - if it's the next id to be inserted, using AUTO_INCREMENT would be safer. SELECT statements are generally given higher priority over INSERT/UPDATE/DELETE, and thus can read before an insert from another source -- which would risk duplicates.
Because you are returning one row, you should do something like:
$query = 'SELECT MAX(ID) as maxidpost FROM wp_posts';
$result = mysql_query($query) or die(mysql_error());
$row = mysql_fetch_row($result);
$postid = $row['maxidpost']+1;
echo "p=$postid";
Otherwise seems about as good as you could do.
You can recalculate the post code after each post. Start with zero. Select it from the database, use that id, add one, save back to database.
Or you could use auto increment (if that is possible).

PHP - Select a unique mysql line without while [duplicate]

This question already has answers here:
Single result from database using mysqli
(6 answers)
Closed 6 months ago.
I want to select only unique values with php/mysql.
I can do it with many line, but I forget how to do it without while... :)
Thanks a lot.
Here is the code that I want to do without while.
$request_1m = "SELECT date1, date2 from mytable";
$result_1m = mysql_query($request_1m,$db);
while($row = mysql_fetch_array($result_1m))
{
/* Get the data from the query result */
$date1_1m = $row["date1"];
$date2_1m = $row["date2"];
}
mysql_fetch_assoc + SELECT with DISTINCT
I'm not sure I understand your question, but here's what I think you want to do :
$request_1m = "SELECT date1, date2 from mytable";
$result_1m = mysql_query($request_1m,$db);
list($date1_1m, $date2_1m) = mysql_fetch_row($result_1m);
Note that this will only get the first row from the result set (just as if you LIMIT 1)
like this?
$dbresult = mysql_query("SELECT DISTINCT field FROM table");
$result = array();
while ($row = mysql_fetch_assoc($dbresult))
{
$result[] = $row;
}
This gets you all unique values from "field" in table "table".
If you really wish to avoid the while loop, you can use the PHP PDO objects, and in particular call the PDO fetchAll() method to retrieve the complete results array in one go. PDO fetchAll() documentation
$db = new PDO('dblib:host=your_hostname;otherparams...');
$db->query("SELECT DISTINCT col FROM table");
$results = $db->fetchAll();
// All your result rows are now in $results
Heres how I do it and Json encode after. This will ensure it will encode only UNIQUE json Values (Without duplicates) as an example
$tbl_nm = "POS_P";
$prod_cat = "prod_cat";
//Select from the POS_P Table the Unique Product Categories using the DISTINCT syntax
$sql = "SELECT DISTINCT $prod_cat FROM $tbl_nm";
//Store the SQL query into the products variable below.
$products = mysql_query($sql);
if ($products){
// Create an array
$rows = array();
// Fetch and populate array
while($row = mysql_fetch_assoc($products)) {
$rows[]=$row;
}
// Convert array to json format
$json = json_encode(array('Categories'=>$rows));
echo $json;
}
//Close db connection when done
mysql_close($con);
?>
That is very easy, take out the while, like below
$row = mysqli_fetch_assoc($result);
$date1_1m = $row["date1"];

Simple way to read single record from MySQL

What's the best way with PHP to read a single record from a MySQL database? E.g.:
SELECT id FROM games
I was trying to find an answer in the old questions, but had no luck.
This post is marked obsolete because the content is out of date. It is not currently accepting new interactions.
$id = mysql_result(mysql_query("SELECT id FROM games LIMIT 1"),0);
$link = mysql_connect('localhost','root','yourPassword')
mysql_select_db('database_name', $link);
$sql = 'SELECT id FROM games LIMIT 1';
$result = mysql_query($sql, $link) or die(mysql_error());
$row = mysql_fetch_assoc($result);
print_r($row);
There were few things missing in ChrisAD answer. After connecting to mysql it's crucial to select database and also die() statement allows you to see errors if they occur.
Be carefull it works only if you have 1 record in the database, because otherwise you need to add WHERE id=xx or something similar to get only one row and not more. Also you can access your id like $row['id']
Using PDO you could do something like this:
$db = new PDO('mysql:host=hostname;dbname=dbname', 'username', 'password');
$stmt = $db->query('select id from games where ...');
$id = $stmt->fetchColumn(0);
if ($id !== false) {
echo $id;
}
You obviously should also check whether PDO::query() executes the query OK (either by checking the result or telling PDO to throw exceptions instead)
Assuming you are using an auto-incrementing primary key, which is the normal way to do things, then you can access the key value of the last row you put into the database with:
$userID = mysqli_insert_id($link);
otherwise, you'll have to know more specifics about the row you are trying to find, such as email address. Without knowing your table structure, we can't be more specific.
Either way, to limit your SELECT query, use a WHERE statement like this:
(Generic Example)
$getID = mysqli_fetch_assoc(mysqli_query($link, "SELECT userID FROM users WHERE something = 'unique'"));
$userID = $getID['userID'];
(Specific example)
Or a more specific example:
$getID = mysqli_fetch_assoc(mysqli_query($link, "SELECT userID FROM users WHERE userID = 1"));
$userID = $getID['userID'];
Warning! Your SQL isn't a good idea, because it will select all rows (no WHERE clause assumes "WHERE 1"!) and clog your application if you have a large number of rows. (What's the point of selecting 1,000 rows when 1 will do?) So instead, when selecting only one row, make sure you specify the LIMIT clause:
$sql = "SELECT id FROM games LIMIT 1"; // Select ONLY one, instead of all
$result = $db->query($sql);
$row = $result->fetch_assoc();
echo 'Game ID: '.$row['id'];
This difference requires MySQL to select only the first matching record, so ordering the table is important or you ought to use a WHERE clause. However, it's a whole lot less memory and time to find that one record, than to get every record and output row number one.
One more answer for object oriented style. Found this solution for me:
$id = $dbh->query("SELECT id FROM mytable WHERE mycolumn = 'foo'")->fetch_object()->id;
gives back just one id. Verify that your design ensures you got the right one.
First you connect to your database. Then you build the query string. Then you launch the query and store the result, and finally you fetch what rows you want from the result by using one of the fetch methods.
$link = mysql_connect('localhost','root','yourPassword')
mysql_select_db('database',$link);
$sql = 'SELECT id FROM games'
$result = mysql_query($sql,$link);
$singleRow = mysql_fetch_array($result)
echo $singleRow;
Edit: So sorry, forgot the database connection. Added it now
'Best way' aside some usual ways of retrieving a single record from the database with PHP go like that:
with mysqli
$sql = "SELECT id, name, producer FROM games WHERE user_id = 1";
$result = $db->query($sql);
$row = $result->fetch_row();
with Zend Framework
//Inside the table class
$select = $this->select()->where('user_id = ?', 1);
$row = $this->fetchRow($select);
The easiest way is to use mysql_result.
I copied some of the code below from other answers to save time.
$link = mysql_connect('localhost','root','yourPassword')
mysql_select_db('database',$link);
$sql = 'SELECT id FROM games'
$result = mysql_query($sql,$link);
$num_rows = mysql_num_rows($result);
// i is the row number and will be 0 through $num_rows-1
for ($i = 0; $i < $num_rows; $i++) {
$value = mysql_result($result, i, 'id');
echo 'Row ', i, ': ', $value, "\n";
}
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$db = new mysqli('localhost', 'tmp', 'tmp', 'your_db');
$db->set_charset('utf8mb4');
if($row = $db->query("SELECT id FROM games LIMIT 1")->fetch_row()) { //NULL or array
$id = $row[0];
}
I agree that mysql_result is the easy way to retrieve contents of one cell from a MySQL result set. Tiny code:
$r = mysql_query('SELECT id FROM table') or die(mysql_error());
if (mysql_num_rows($r) > 0) {
echo mysql_result($r); // will output first ID
echo mysql_result($r, 1); // will ouput second ID
}
Easy way to Fetch Single Record from MySQL Database by using PHP List
The SQL Query is SELECT user_name from user_table WHERE user_id = 6
The PHP Code for the above Query is
$sql_select = "";
$sql_select .= "SELECT ";
$sql_select .= " user_name ";
$sql_select .= "FROM user_table ";
$sql_select .= "WHERE user_id = 6" ;
$rs_id = mysql_query($sql_select, $link) or die(mysql_error());
list($userName) = mysql_fetch_row($rs_id);
Note: The List Concept should be applicable for Single Row Fetching not for Multiple Rows
Better if SQL will be optimized with addion of LIMIT 1 in the end:
$query = "select id from games LIMIT 1";
SO ANSWER IS (works on php 5.6.3):
If you want to get first item of first row(even if it is not ID column):
queryExec($query) -> fetch_array()[0];
If you want to get first row(single item from DB)
queryExec($query) -> fetch_assoc();
If you want to some exact column from first row
queryExec($query) -> fetch_assoc()['columnName'];
or need to fix query and use first written way :)

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