I need to format a floating point number in PHP so it can be inserted into a column in a table which is of type decimal(6,5).
So,
20 would get formatter to 20.00000
20.5 would get formatted to 20.50000
How to do it in PHP?
To avoid the float inherent precision error,
cast first to decimal(9,2), then to decimal(6,5).
To format a number just use
<?php
echo number_format(20, 5); //returns 20.00000
echo number_format(20.5, 5); //returns 20.50000
?>
But you don't need to do that to insert into a MySQL DB.
Related
I have a PHP code that will compute the balance of the quantity but it gives me a negative value as a balance quantity as shown in the image below.
I tried to check the quantities if what's causing the problem and try to var_dump the quantity. after checking using var_dump, it shows that the data type of my quantity is string while my balance quantity is float.
so far, I have my code below:
$query_po_quantity = mysqli_query($new_conn, "SELECT quantity, po_number FROM purchase_order WHERE supplier_name = '$supplier_name' AND category_name = '$category_name' AND activity = '$activity' AND description = '$description'");
$row = mysqli_fetch_assoc($query_po_quantity);
$po_quantity = $row['quantity'];
$po_number = $row['po_number'];
$query_rr_quantity = mysqli_query($new_conn, "SELECT SUM(total_received) AS quantity FROM receiving_reports WHERE po_number = '$po_number' AND category_name = '$category_name' AND activity = '$activity' AND description = '$description'");
$row = mysqli_fetch_assoc($query_rr_quantity);
$rr_quantity = $row['quantity'];
$balance = $po_quantity - $rr_quantity;
$supplier_name = preg_replace('/\\\\/', '', $supplier_name);
echo $po_quantity.' - '.$rr_quantity.' = '.$balance.'<br />';
This is the output:
how can I get the actual balance?
The reason you're getting an incorrect result when calculating 0.42 - 0.420000000000000000004 is due to errors with floating point precision. This is due to the way floating point numbers are stored, and both MySQL and PHP are susceptible to floating point errors if done incorrectly, but they also both have ways to prevent them when you do need highly precise calculations. With floating point types only the approximate value is stored and attempts to treat them as exact values in comparisons may lead to problems.
For PHP, this means you need to use either the arbitrary precision math functions or gmp functions. For MySQL, you need to be storing the numbers using the DECIMAL format with the desired precision you require.
First thing's first, you need to change the data type of your column in MySQL to DECIMAL, not a string. Strings are inappropriate to store numbers. Even if you were using a FLOAT or DOUBLE to store your values
your code may have actually worked, because these values likely would have been rounded.
Next, seeing as the value 0.420000000000000000004 came from a string stored in your database, I'm assuming the error stems from whatever calculations you did using PHP beforehand when you were calculating the value to be inserted. You will need to update this code to use precise math.
Use number_format:
$rr_quantity = number_format($row['quantity'], 2);
Float variable range 1.7E-308 and 1.7E+308 so it's give 15 digits of accuracy. Use number format
I am trying many typed of fields in MySQL to store numbers only, tried with INT, BIGINT with leading zeros, CHAR and VARCHAR to store INVOICE NUMBERS
I need the invoice numbers to be start with 0000000001, I stored it manually in PHPmyadmin
Now I want to display it and I dont get the leading zeros ....
Here is the database
field "folio" CHAR 15 stored I have manually did 0000000001 it displays fine on phpmyadmin
but here is the problem
<?php $maxprod=mysqli_query($datacenter,
"SELECT * FROM ventas
WHERE documento = 'boleta'
ORDER BY id DESC LIMIT 1");
while($lastcode=mysqli_fetch_assoc($maxprod)){?>
<input type="text" value="<?php echo $lastcode['folio']+1?>">
<?php }?>
the result of the query is 1 just 1 it does not display all other zeros
Any idea why?
PHP automatically converts string into number if you are performing any numerical operation on it. But you can keep the order number in integer form and pad it with zeroes when necessary:
str_pad($lastcode['folio']+1, 15, "0", STR_PAD_LEFT);
echo $lastcode['folio'] should show you a result with the leading zeroes, but not $lastcode['folio']+1.
As soon as you do that +1, the result is no longer a string. The $lastcode['folio'] variable is converted to a number in order to do the arithmetic operation on it.
The leading zeroes are just formatting and don't need to be stored with the number. If you need an autoincrementing number, just use an autoincrement integer in MySQL, and format the number with leading zeroes when you print it out.
This will retrieve the number as a string to display it as text.
Later you can manipulate it on your coding environment.
SELECT CAST(document_number AS CHAR) FROM ...
I was trying to export database query to CSV and the need arised to use different decimal comma. It seems impossible to change the decimal comma in MySQL, so I tried in PHP:
setlocale(LC_NUMERIC, "cs_CZ");
But it seems that all the database functions like mysql_fetch_row and mysql_fetch_assoc are retrieving data of type string instead of double:
$res = mysql_query("select 50/3");
$row = mysql_fetch_row($res);
var_dump($row); // $row[0] is of type "string"
So in general PHP already doesn't have data of type double, but only strings!
So is there some general, clean way to specify output of the decimal point?
I ended up converting the strings using str_replace('.', ',', $row[0]) but this is ugly for two reasons:
you have to know which field is of type double
it's a dirty string job.
I don't know which database client/driver you're using but there is something like mysql_field_typeDocs which gives you the type based on it's offset, like 0.
This should do the job to find out if a certain column needs re-formatting or not.
To reformat, there is number_formatDocs.
With these you can do the conversion automatically.
Edit: Regarding your comments:
If you want to get PHP datatypes mapped, consider using the MySQL Native DriverDocs. Use it together with PDO:
Advantages of using mysqlnd for PDO
mysqlnd returns native data types when using Server-side Prepared Statements, for example an INT column is returned as an integer variable not as a string. That means fewer data conversions internally. Source
So depending of what you try to achieve, use the right tool.
See as well the multiple options you have when fetching data from a PDO StatementDocs.
// French notation
$nombre_format_francais = number_format($number, 2, ',', ' ');
Try
number_format($row[0], 2, ",", ".");
That should change the format of the number. (german format)
i am using $_GET['var'] to get a variable then compare it with a variable in my database. the variable is 1.1 the var is set to "float" on the database so i know it can handle decimals but when i compare them with the code below i get nothing.
include 'connect.php';
$sql=mysql_query("SELECT * FROM table WHERE stuff='$stuff'");
while ($row=mysql_fetch_assoc($sql)) {
$start=$row['start'];
}
echo $start; //nothing happens
From what I know float type isn't precise. It doesn't show you that actual value so 1.1 that you saved may not be the actual value stored. Trying setting your field as decimal and give it a length of say, 10,1 where 10 is the maximum number of digits (the precision) and 1 is the number of digits to the right of the decimal point (the scale). It should work doing query like stuff='1.1' or stuff=1.1.
WHERE stuff = '$stuff' is a String comparison.
Compare number like so
WHERE stuff = $stuff
Don't use float( even if you insert 1.1 into the table, the actual value for float type is not 1.1, but something like 1.100000023841858) . Change it to double in database (or decimal)
You might not be seeing any output because your echo is outside the loop.
The scope of your variable $start would be confined to the loop.
Change the stuff field to DOUBLE type.
Then,
SELECT * FROM table WHERE stuff=$stuff
this should be the sql query
I store money values in my db table. E.g. I have 2.50. But when I print that value the 0 is always missing so I get 2.5. The db table money field has the following type: decimal(6,2)
any idea how to fix that?
By default PHP echo and print don't print the trailing zeros of a floating point number.
To overcome this you need to use printf as:
$money = 2.50;
printf("%.2f",$money); // prints 2.50
echo $money; // prints 2.5
print $money; // prints 2.5
The format specifier used in printf is "%.2f" what it means is always print atleast two digits after the decimal point and if there are not so many digits use 0. Note that it is atleast two digits not equal to two digits. So if I print 1.234 with that format it will not truncate it to 1.23 but will print 1.234 and if I print 1 it will result in 1.00