Reading data from mysql table [closed] - php

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In my database table, I have a lot of questions ,each having a category . Say, there are 100 questions and some number of categories which I don't know . I want to know the number and the names of the categories.
Please tell the way to do it in php.


You can try something like this
$con=mysqli_connect("localhost","my_user","my_password","my_db");
// Check connection
if (mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
// Perform queries
$result = mysqli_query($con,"SELECT category_name FROM your_table GROUP BY category_name");
$count = mysqli_num_rows($result); // no of categories
while ($row=mysqli_fetch_row($result)) {
echo $row[0]; // printing category name
}


How about...
<?php
$mysqli = mysqli_connect( /* info */) or die ("MySQL error");
$result = mysqli_query("SELECT COUNT(DISTINCT `category`)");
echo $result;
?>
That is assuming categories are all in a single column.

Related

What is wrong with this mysql query? help please [closed]

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I am trying to select a table and I don't know what I am doing wrong:
$result = mysql_query('SELECT * FROM sfat WHERE done="0" LIMIT 0,10');
$row = mysql_fetch_array($result)
$url = $row["web"];

use
while ($row = mysql_fetch_array($result) ) {
$url = $row["web"];
echo $url;
}
in stead of
$row = mysql_fetch_array($result)
$url = $row["web"];
Because your query indicates you are expecting up to 10 rows. But your code will only show the first one.

The following example will be used to create database
<?php
$con=mysqli_connect("hostname","username","password");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
// Create database
$sql="CREATE DATABASE my_db";
if (mysqli_query($con,$sql))
{
echo "Database my_db created successfully";
}
else
{
echo "Error creating database: " . mysqli_error($con);
}
?>

PHP: How to check if no rows are returned [closed]

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With the following PHP code, how do i check if there's no row retuned so i can echo some message?
PHP:
<?php
require_once 'db_conx.php';
$Result = mysql_query("SELECT * FROM ads WHERE pid = '2'")
or die (mysql_error());
while($row = mysql_fetch_array($Result)){
echo '<span class="classPid" style="display:none">'.$row['pid'].'</span>';
}
?>
Thanks

There are a number of ways to do this. There is a specific function mysql_num_rows() which will return the number of rows returned.
mysql_num_rows($Result);
This will return 0 if there are no rows affected or returned.
You could also create some conditions using mysql_fetch_array. mysql_fetch_array will return FALSE if there are no rows.
On a separate note it would be a good idea to update your connection
and functions to mysqli as mysql is no depreciated.
See docs on mysql_num_rows().
http://www.php.net/mysql_num_rows

Something like this
<?php
require_once 'db_conx.php';
$Result = mysql_query("SELECT * FROM ads WHERE pid = '2'")
or die (mysql_error());
$i=0;
while($row = mysql_fetch_array($Result)){
echo "<span class='classPid' style='display:none'>".$row['pid']."</span>";
$i++;
}
if($i==0){
echo "No rows found";
}
?>

Is this the correct way to call a sql database? [closed]

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Hey I was wondering if my ip_address is 0 and I want to check all tables that have a 0 ip_address and then execute a function of that. So something like this code:
mysql_connect(db_server, db_user, db_pass);
$ipzerouseroffline = mysql_db_query(db_name,"SELECT ip_address = '0' FROM user");
if ( $ipzerouseroffline == 0 ) {
//THEN CODE GOES HERE
}
Is that the correct way to write? If the ip_address is zero then the code passes.

I think this is what you want:
$con = mysqli_connect(db_server, db_user, db_pass, db_name);
$result = mysqli_query($con,"SELECT * FROM user WHERE ip_address = '0'");
while($row = mysqli_fetch_array($result)){
//CODE
}
mysqli_close($con);

Can this code work or not [closed]

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Can the code below work or not to retrieve data from database and display.. I know that the sql4 can't work in a mysql database can the php code below make it work or not.
<?php
include 'connect.php';
$sql2 = "SELECT * from pm Order by mid";
while ($row3 = mysql_fetch_array($sql2)) {
$sql4 = mysql_query("SELECT * FROM reply ORDER BY mid =".$row3["$mid"]." ");
$row4 = mysql_fetch_array($sql4);
echo"<trid='".$mid."'><td><img src='a/$name' width='150' height='100' /></td> <td>".$row['mid']."</td></tr><tr><td>".$row['reply']."</td></tr>";
}
?>
esp. this mysql or mysql and php combined. Basically is the code below improper. I think it is.
<?php
$sql4 = mysql_query("SELECT * FROM reply ORDER BY mid =".$row3["$mid"]." ");
?>

Put the following at the top of your PHP file and try it out yourself:
<?php
error_reporting(-1);
ini_set("display_errors", true);
// Your code goes here
?>
(I think the code is self-explaining)

Try...
$sql2 = "SELECT * from pm Order by mid";
$result = mysql_query($sql2); <- MISSING THIS LINE
while ($row3 = mysql_fetch_array($result))
{
// OTHER CODE HERE
}

Convert Json Array to Strings [closed]

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I have my result in json array format, I want to change my array results to json string format. How do I do this. Please help.. i dont have idea how i go about doing this :(. new to json
My result as json array is like this
[["Date.UTC(2011,09,03)","1"],["Date.UTC(2011,09,06)","53"],["Date.UTC(2011,09,07)","178"],["Date.UTC(2011,09,08)","305"],["Date.UTC(2011,09,09)","152"],["Date.UTC(2011,09,11)","20"],["Date.UTC(2011,09,12)","239"],["Date.UTC(2011,09,13)","25"],["Date.UTC(2011,09,14)","316"],["Date.UTC(2011,09,15)","169"],["Date.UTC(2011,09,16)","20"],["Date.UTC(2011,09,19)","126"]
My code
$mysql_connect = mysql_connect($db_host, $db_user, $db_pword, $db_name);
$query = "Select DATE_FORMAT(`timestamp`,'%Y,%m,%d') as date, Count(*) as frequency from mytable group by date_format(`timestamp`,'%Y,%m,%d')";
if (!$mysql_connect) die("unable to connect to database: " . mysql_error());
#mysql_select_db($db_name) or die( "Unable to select database");
$result = mysql_query($query);
$response = array();
if($result === FALSE)
{
die(mysql_error()); // TODO: better error handling
}
while($row=mysql_fetch_array($result))
{
$date = "Date.UTC(".$row ['date'].")";
$frequency =$row['frequency'];
$response[] = array ($date,$frequency);
}
JSONArray jArray;
String s = jArray.toString();
mysql_close($mysql_connect);

json_encode:
<?php
$json_string = json_encode($your_array);
Did you even bother to Google this?

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