I just create a Remote MySQL access from my other database server (remote) and I can see tables in it :
// SHOW ALL TABLES NAME
$sql = "SHOW TABLES";
$result = mysqli_query($conn, $sql);
while ($row = mysqli_fetch_row($result)) {
echo "Table: {$row[0]} <br>" ;
}
I can also see what columns name on each tables by using this :
// SHOW COLUMNS NAME OF A TABLE
$sql = 'DESCRIBE wp_ps_product_sku';
$result = mysqli_query($conn, $sql);
while ($row = mysqli_fetch_row($result)) {
echo "Column: {$row[0]} <br>" ;
}
but why I can't see any rows inside each table?
$sql = 'SELECT * wp_ps_product_sku';
$result = $conn->query($sql);
print_r($result);
it always gives me an empty result. for any tables. same result. it's always empty. what did I missed here? is it possible that server just give me an access to read the database structure only, but not the data?
thank you.
On your select statement, you are missing the 'from' clause.
select * from wp_ps_product_sku;
I am a novice when it comes to PHP but I don't understand if my syntax is wrong in this statement, or how would I grab an int from my MySQL server.
I know that my server credentials are working fine. How would I fix this statement to give me a returned integer of the number of reviews in the userinfo table?
$numberofpreviousreviews = mysql_query("SELECT `number_of_reviews` FROM `userinfo`") or die(mysql_error()); //Check to see how many reviews user has previously created
$amountofreviews = $numberofpreviousreviews + 1;
$query2 = mysql_query("ALTER TABLE userinfo ADD `amountofreviews` VARCHAR(10000)") or die(mysql_error()); //Make another column in database for the new review
You need to fetch your results after you run your query. There are several ways to do this but using mysql_fetch_assoc() will work for you.
$numberofpreviousreviews = mysql_query("SELECT `number_of_reviews` FROM `userinfo`") or die(mysql_error()); //Check to see how many reviews user has previously created
$row = mysql_fetch_assoc($numberofpreviousreviews);
$amountofreviews = $row['number_of_reviews'] + 1;
FYI, you shouldn't be using mysql_* functions anymore. They are deprecated and going away. You should use mysqli or PDO.
Assume you have a table userinfo which has the following structure and data :
Scenario #1 :
If you want to retrieve the all number_of_reviews, then do like this,
$query = "SELECT `number_of_reviews` FROM `userinfo`";
$result = mysqli_query($db,$query);
while ($row = mysqli_fetch_assoc($result)) {
echo "Number of reviews : " . $row['number_of_reviews'] . "<br/>";
}
It will give you,
Number of reviews : 20
Number of reviews : 40
Since, the result has many rows, it will display like above.
Scenario #2:
If you want to retrieve only the specific number_of_reviews for some user id (which is unique). I take id as 1 as a example here. Then do like,
$query2 = "SELECT `number_of_reviews` FROM `userinfo` WHERE `id` = 1";
$result2 = mysqli_query($db,$query2);
while ($row2 = mysqli_fetch_assoc($result2)) {
echo $row2['number_of_reviews'] . "<br/>";
}
This will print,
20.
Because, number_of_reviews is 20 for id 1.
I'm new to PHP and I was wondering how to select a specific column from a row. For example if I wanted to display the first name of Joe Bugly where ID, first name, last name, and email are all columns.
Assuming that you don't want all columns that would be returned with select * from ... (a), you can simply list the desired columns explicitly:
select fname, lname from ...
For example, suppose you know your user ID is jbug01 and you just want the corresponding email address:
select email
from users
where userid = 'jbug01'
In terms of doing this within PHP, the following code snippet may help:
<?php
$conn = mysql_connect ("localhost", "paxdiablo", "supersekritsauce");
if (!$conn) {
die ('Could not connect: ' . mysql_error());
}
mysql_select_db ("my_database", $conn);
$result = mysql_query ("select email from users where userid = 'jbug01'");
while ($row = mysql_fetch_array ($result)) {
echo $row['email'] . "<br />";
}
mysql_close ($conn);
?>
(a) There are precious few cases where selecting * makes sense (other than tools that need to get all columns such as DB viewers).
You should usually prefer to be explicit with your column selections. This may allow you to detect problems with schema changes much earlier in the process than will be the case if you just blindly select everything.
It will also result in less information being transmitted which may not be important for small databases or systems where everything runs on the same box but it will affect scalability of your system, both in terms of data size and distribution across a network.
Try this:
$conn = mysql_connect("localhost","root");
mysql_select_db("DbName",$conn);
$query = "Select u.FirstName from Users u";
$results = mysql_query($query);
while($row = mysql_fetch_array($results)){
echo $row['FirstName'];
}
Try this:
$db = new PDO('mysql:host=hostname;dbname=dbname', 'username', 'password');
$stmt = $db->query('select id from games where ...');
while ($id = $stmt->fetchColumn(0)) {
echo $id;
}
Mark answer if this helps.
Reference
This is actually an SQL question ;)
Depends on how you are selecting record of Joe Bugly. If you are selecting on basis of ID, then
SELECT fname
FROM your_table_name
WHERE ID = <ID of Joe Bugly>
This way you have selected a record and by applying fname in SELECT clause, you are filtering the number of columns you want
I want to display a list of all the databases on my server, when I do this:
echo mysql_query(" SHOW DATABASES ");
I get this error:
Resource id #3
So how to do it?
You need to retrieve a result set from the query, like so:
$set = mysql_query('SHOW DATABASES;');
$dbs = array();
while($db = mysql_fetch_row($set))
$dbs[] = $db[0];
echo implode('<br/>', $dbs);
It's clear that you're new to PHP, so here's a huge tip.
The "mysql" extension is old and busted. Don't use it, and stop reading any tutorials that tell you it's the thing to use.
Instead, learn PDO, it works for most database engine and helps you do the right thing. Here's an example:
$dbh = new PDO('mysql:host=localhost;user=foo;password=bar;dbname=baz');
$statement = $dbh->query('SHOW DATABASES');
print_r( $statement->fetchAll() );
Jacob Relkin's solution is very good.
However, if you are using MySQL 5.x, I would only change one thing:
Instead of using SHOW DATABASES; I would use this query
SELECT schema_name FROM information_schema.schemata;
To list just the useful Databases, and not the system ones:
$query = "SELECT schema_name FROM information_schema.schemata WHERE schema_name
NOT IN ('information_schema', 'mysql', 'performance_schema')";
$result = mysqli_query($link, $query) or die(mysqli_error($link));
$dbs = array();
while($db = mysqli_fetch_row($result))
$dbs[] = $db[0];
echo implode('<br/>', $dbs);
Your MySQL user should have full access, otherwise you will see only the databases where you have at least read permissions.
you're getting a query result set. You need to retrieve the result rows like this:
$r = mysql_query("SHOW DATABASES");
while ($row = mysql_fetch_assoc($r)) {
print_r($row);
}
that aught to do it
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.
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$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 :)