Hi i have a php form and part of this is to get the last "shiftID" row entry in my table and put this into a variable so i can later add 1 to said variable. However the result of the following code returns the information linked below. How do i get the last "shiftID" number by itself into a variable.
<?php
session_start();
include 'dbh.php';
$start = $_GET['starttime'];
$finish = $_GET['finishtime'];
$dat = $_GET['date'];
$id = $_GET['userid'];
$shiftidd = $conn->query("SELECT shiftID FROM shift_user ORDER BY shiftID DESC LIMIT 1");
$row = mysqli_fetch_row($shiftidd);
echo print_r($row[0]);
//$result = $conn->query("INSERT INTO shift (shiftStart, shiftFinish, shiftDate)
//VALUES ('$start', '$finish', '$dat')");
//$sql = $conn->query("INSERT INTO shift_user (shiftID, userID) VALUES ('$shiftidd', '$id')");
//header("Location: shifts.php");
?>
Web page result:
"connected 41"
I'm looking for the number "4" but I'm guessing the "1" is the affected row along with the result? but how do i get rid of the "1"?
Thanks in advance.
1 is a result of print_r() which is superfluous here. Use either echo or print_r, but not both
You can do it like. After you insert query executed use the following function
mysql_query("INSERT INTO Persons (FirstName,LastName,Age)
VALUES ('Glenn','Quagmire',33)");
$id = mysql_insert_id();//will return you the last id inserted into table//
But if you want to find the last id of some table then you have to use the follwoing code:
$shiftidd = $conn->query("SELECT MAX(shiftID) FROM shift_user LIMIT 1");
$row = mysqli_fetch_row($shiftidd);
echo print_r($row[0])///////it will be the last id of the table////////
if you want to find next id please try this
$shiftidd = $conn->query("SELECT MAX(shiftID)+1 FROM shift_user LIMIT 1");
$row = mysqli_fetch_row($shiftidd);
echo print_r($row[0])///////it will be the next id of the table///////////
I am trying to retrieve the last ID from the database and increment it by one. My problem is that I am not able to retrieve it in a particular category. For instance, I have categories with a string value of A, B and C. The category with a string value of A will return only id starting from 1 as 10001, 10002 and the last ID to be retrieved is 10002 plus 1 so that the ID to be displayed is 10003.
Category "B" will return 20002 and category "C" will return 30002.
Here is my code:
<?php
$con = mysql_connect("server","username","password","db_name") or die (mysql_error());
mysql_select_db($con, 'db_name');
$sql = "Select `id` from `tbl_violation` WHERE `category` = 'A' ORDER BY `category` DESC LIMIT 1";
$result = mysql_query ($sql,$con);
while($row = mysql_fetch_array($result, $con))
{
$i = $row['id'];
$i++;
echo "DLR - " .$i;
}
?>
The error is this:
Warning: mysql_fetch_array() expects parameter 1 to be resource, boolean given in ...
Notice: Undefined variable: i in ...
First I must say again... Stay away from mysql_connect() and all other mysql_* functions. If you want a simple fix, just replace it with mysqli_ functions and make sure you escape ALL user provided input. A bit of reading But I would recommend to look into PDO.
That out of the way, your MYSQL problem is easy. You want to GROUP the elements so all the rows with same category column are groupped together and then select the maximum for each group. Your SQL would then be:
SELECT category, MAX(id) AS highest_id FROM tbl_violation GROUP BY category;
see this fiddle I made with a similar table.
You can then access the results you get from mysqli_query function the same way you do now...
while($row = mysqli_fetch_array($result, $con))
{
$i = $row['highest_id'];
$i++;
$category = $row['category'];
echo "$category - $i";
}
You can use SELECT MAX to get the highest id. I am assuming that id is not unique. If so, remove the WHERE statement from the query. Try the following.
<?php
$con = mysql_connect("server","username","password","db_name") or die (mysql_error());
mysql_select_db("database");
$sql = "Select MAX(`id`) from `tbl_violation` WHERE `category` = 'A";
$result = mysql_query ($sql,$con);
while($row = mysql_fetch_array($result))
{
$i = $row['id'];
echo "DLR - " .$i++;
}
?>
Also I would like to add that I agree with flynorc. Use PDO or mysqli.
Use
ORDER BY `id` DESC
Instead of
ORDER BY `category` DESC
I am trying to get the last value of a field during a new registration.
before insert data into the table, I want to create a user id number according to the last registered user's id number. to do that I use this:
//to reach the last value of userID field;
$sql = "SELECT userID FROM loto_users ORDER BY userID DESC LIMIT 1";
$result = mysql_query($sql);
while($row = mysql_fetch_array($result))
{
$value = $row['userID'];
echo "$value"; //not resulting here
}
$userID = $value+1;
so, the userID becomes 1.
The weird thing is, I could capable to use exact same code in another php file and works fine.
I would like to say that, rest of the code works fine. No problem with db connections or any other things you can tell me.
Note that: When I run the same query line in the mysql interface, I can get the value I want. I mean $sql line.
Your problem is in this code:
{
$svalue = $row['userID'];
----^
echo "$value"; //not resulting here
}
$userID = $value+1;
Change to $value.
But the right answer is to define userID to be auto-incrementing. That way, the database does the work for you. After inserting the row, you can do:
SELECT LAST_INSERT_ID()
To get the last value.
I solved the problem. Here;
$sql = "SELECT userID FROM loto_users ORDER BY userID DESC LIMIT 1";
$result = mysql_query($sql);
$user_info = $result->fetch_assoc();
$value = intval($user_info["userID"]);
$userID = $value+1;
Thanks everyone.
If you mark the userID field as autoincrement in you mysql table.
You won't need to set the userID and db increase the userID for you. You can get the assigned userID using the mysql_insert_id() function. Here is an example from php.net
mysql_query("INSERT INTO mytable (product) values ('kossu')");
printf("Last inserted record has id %d\n", mysql_insert_id());
Here is another example for your case
mysql_query("INSERT INTO 'loto_users'('username',...) values('usernameValue',...)");
echo "New User id is ".mysql_insert_id();
I have this code:
$local_id = $_GET['id'];
$sql = dbquery("SELECT * FROM `videos` WHERE `id` = ".$local_id." LIMIT 0, 1");
while($row = mysql_fetch_array($sql)){
$video_id = $row["youtube_id"];
// the rest
}
how can i check if $local_id does not exist in the db and display an error?
mysql_num_rows
if(mysql_num_rows($sql) == 0) {
//Show error
}
$sql = dbquery("select count(*) from videos where id = ".$local_id." LIMIT 0, 1");
$row = mysql_fetch_row($sql);
if($row[0] == 0)
echo 'error';
You can use the following query:
"SELECT COUNT(*) FROM `videos` WHERE `id` = ".mysql_real_escape_string($local_id)
This query will return one number: how many records have matched your query. If this is zero, you surely know that there are no records with this ID.
This is more optimal than other solutions posted in case you only want to check for the existence of the ID, and don't need the data (if you use SELECT * ..., all the data will be unnecessarily sent from MySQL to you). Otherwise mysql_num_rows() is the best choice, as #Ryan Doherty correctly posted.
Be sure to ALWAYS escape data that came from the outside (this time GET) before you put it into a query (mysql_real_escape_string() for MySQL).
If you fail to do so, you are a possible victim for SQL Injection.
You could have a $count variable and increment it in the while loop. After the loop, check the count, if it is 0, then echo an error message.
What's the best way with PHP to read a single record from a MySQL database? E.g.:
SELECT id FROM games
I was trying to find an answer in the old questions, but had no luck.
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$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 :)