I have 2 tables :
table names transaction and detail customer
transaction table fields are idtrans and idcust.
detail customer fields are idcust and custname.
i have Problem with my php syntax, i want select table with condition from value lopping, here's my code:
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql="select * from transaction";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
$sqlid="select * from detailcust where idcust='$row[idcust]')";
$resultid= $conn->query($sqlid);
if ($resultid->num_rows > 0){
while ($rowid= mysqli_fetch_array($resultid)){
$custname=$rowid["custname"];
echo $custname;
}
result name always first idcust value.
You seem to want the names of customer that have at least one transaction. If so, no need for loops and multiple queries. You can get the result you want with just one query:
select c.*
from detailcust c
where exists (select 1 from transaction t where t.idcust = c.idcust)
Related
I have a table with 4 rows, I need to multiply col. 1 and 2 and put the results in col. 1 in the 2nd table. do the same with the other two cols' from table 1.
I'm sure its simple code. I just don't know MySQL
Get the values fetch the rows and insert again to the table 2:
$mysqli = new mysqli('127.0.0.1', 'tu_usuario', 'tu_contraseña', 'sakila');
if ($mysqli->connect_errno) {
echo "Errno: " . $mysqli->connect_errno . "\n";
echo "Error: " . $mysqli->connect_error . "\n";
exit;
}
$sql = "SELECT column1, column2 FROM table1";
if ($result = $mysqli->query($sql)) {
/* fetch object array */
while ($row = $result->fetch_row()){
$sql2 = "INSERT INTO table2 (col1) VALUES(".$row['column1']*$row['column2'].");";
$result = $mysqli->query($sql);
}
}
I didn't check if there is any error in theses code, it's just an example that shows the idea. I hope will be enough for you the explanation. If you still having doubts please answer again.
Low level question but, I understand that you can select elements from a table using:
$sql = "SELECT blah FROM TABLE WHERE this = 'something' ";
But when I try to select a specific value from my table, where let's say a user has no tries left so if I try to grab how many tries they have left with:
$sql = "SELECT tries FROM table WHERE user = 'something'";
How would I grab that value specifically if it was 5 or 9? I tried setting a variable equal to something I $sql off my table but it doesn't grab the value.
Edit
I have a database that has a table called Item which contains: id, name, value, and stock of a particular item. If a user wants to order that item I will first check it if's in stock with a function, to see if it is not in stock then a error message is printed, otherwise accept the order.
Extremely primitive since I'm just trying to get grab the stock value first.
$query = $_GET['query']; //id I get from the specified item
echo 'the id is: ' .$query.''; //test purposes
$mysql_handle = mysql_connect($dbhost, $dbuser, $dbpass)
or die("Error connecting to database server");
mysql_select_db($dbname, $mysql_handle)
or die("Error selecting database: $dbname");
$sql1 = "SELECT item_stock FROM chat-db.Item WHERE id = '".$query."'";
echo '' .$sql2. ''; //test purposes
whats the correct way to assign the value from that specific stock to a variable?
If you want to grab rows with a set of possible values you can use 'IN' such as:
Get all columns from users table where users have 5 or 9 tries:
SELECT * FROM users WHERE tries IN('5', '9'); or
If you want to select where the user has no tries left, assuming the tries column is a numeric type you can look for rows with 0 tries:
Get all columns from Item table where stock is 0:
SELECT * FROM db_inv.Item WHERE stock = '0';
Get all columns from users table where tries is 0:
SELECT * FROM users WHERE tries = '0';
As for your php code you should be able to do the following:
$query = $_GET['query']; //id I get from the specified item
echo 'the id is: ' . $query; //test purposes
$mysql_handle = mysqli_connect($dbhost, $dbuser, $dbpass) or die("Error connecting to database server");
$sql1 = "SELECT item_stock FROM chat-db.Item WHERE id = '".$query."'";
$results = mysqli_query($mysql_handle, $sql1);
if (!empty($results) && mysqli_num_rows($results) > 0) {
while($rec = mysqli_fetch_array($results)) {
echo $rec['item_stock'];
}
}
SET #rownum:=0;
SELECT #rownum:=#rownum+1 as count, student_name,student_info FROM studnet;
I want to merge this query in code igniter model...
I want output as follows where count is dynamic i.e. increases as record increases :::
count student_name student_info
1 Ram Palpa
2 Shyam Butwal
Using
CodeIgniter's Database Custom Function Calls:
Assuming you have mysqli set in your application/config/database.php:
$db['default']['dbdriver'] = 'mysqli';
Then in your model:
$this->load->database();
// Perform a mysqli_multi_query
$db_id = $this->db->conn_id;
$this->db->call_function("multi_query", $db_id, "SET #rownum:=0; SELECT #rownum:=#rownum+1 as count, student_name,student_info FROM student;"
$this->db->call_function('next_result', $db_id); // Skip the first query in this multi_query since you want the result from the second query
$result = $this->db->call_function("store_result", $db_id);
// Output each row
while($row = $result->fetch_assoc()){
$row['count'] . " ". $row['student_name'] . " " . $row['student_info'] . "\n";
}
I have 2 MYSQL tables and when I pick up dates from table A which contains only 1 column and lets say 10 rows with dates
$result = mysql_query("SELECT * FROM A");
$row = mysql_fetch_assoc($result);
And after I want to UPDATE another table B with using this dates from table A mysql_query("UPDATE B SET something='1' WHERE name='".$row['name']."'")
So i need to update the second table, but its updating just once with first date from table A, and other 9 its ignoring. So my question is, how to make updating of second table with each date from 1 table?
You need to run a the updates in a loop. After executing your query
$result = mysql_query("SELECT * FROM A");
and verifying that it has succeeded (make sure $result is not null), instead of fetching one row, use a loop:
while($row = mysql_fetch_assoc($result)){
// perform calculations & assignments with the $row elements
$result2 = mysql_query("UPDATE B SET something='1'
WHERE name='".$row['name']."'");
if(! $result2){
echo "update failed";
}
// Any other stuff you need to do
}
Alternatively:
If the something in the update is the same for all the rows, you can change your first query to give you a coma-separated string of names:
$result = mysql_query("SELECT CONCAT("'",GROUP_CONCAT(name SEPARATOR "','"),"'")
AS all_names FROM A");
This way, you receive only one row, and you can then use it in your second query:
$result2 = mysql_query("UPDATE B SET something='1'
WHERE name IN (".$row['name'].")");
I'm a MYSQL/PHP newbie and I'm sure this is a simple question. I'm trying to calculate the average of several questions and respondents from one table and updating a Group table with that value.
For example Table answers consists of (name, group_id, TaskClarity1, TaskClarity2, TaskClarity3) in Table B i want (group_id, avg(TaskClarity1,TaskClarity2,TaskClarity3)).
This is what I've got...
$avg_task_clarity_1 = mysql_query("SELECT AVG(TaskClarity1) WHERE gruppid = '$group_id'");
$avg_task_clarity_2 = mysql_query("SELECT AVG(TaskClarity2) WHERE gruppid = '$group_id'");
$avg_task_clarity_3 = mysql_query("SELECT AVG(TaskClarity3) WHERE gruppid = '$group_id'");
$avg_task_clarity = ($avg_task_clarity_1+$avg_task_clarity_2+$avg_task_clarity_3)/3;
$print_task_clarity_1" UPDATE results SET results.TaskClarity = '$avg_task_clarity'";
if (mysql_query($print_task_clarity_1)) { echo $print_task_clarity_1; } else { echo "Error TaskClarity1: " . mysql_error();
First, mysql_query() returns a resource, and you then need to extract information from it. Your query doesn't mantion any table name (I'll call it MyTable).
Also, you can get all three averages with one query.
Here's how I would start:
$table = "MyTable";
$sql = "SELECT AVG(TaskClarity1) AS avgClarity1,
AVG(TaskClarity2) AS avgClarity2,
AVG(TaskClarity3) AS avgClarity1
FROM $table WHERE gruppid = '$group_id'";
$resource = mysql_query($sql); //execute the query
if (! $resource = mysql_query($sql) ){
echo "Error reading from table $table";
die;
}
if (! mysql_num_rows($resource ) ){
echo "No records found in $table";
}
else {
$row = mysql_fetch_assoc($resource); // fetch the first row
$avg_task_clarity_1 = $row['avgClarity1'];
$avg_task_clarity_2 = $row['avgClarity2'];
$avg_task_clarity_3 = $row['avgClarity3'];
$avg_task_clarity =
($avg_task_clarity_1+$avg_task_clarity_2+$avg_task_clarity_3)/3;
//...
// other stuff you want to do
}
Please comment if this is not helpful enough, and I will revise my answer.