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
Related
I'm working on a project using the pages in php / mysql and html; I have a table that contains the data for calls made from a PBX and save the number called, the source, date, time, etc ... what I want to do is to search within this table all the phone numbers that have the first 4 digits equal to those that pass through the query, only that i have no idea how to pull off only the 4-digit or at least how to make a control character by character of the value contained in the field. I tell you now that the field is a varchar. Thank you in advance :)
To do that in MySQL query, either
SELECT *
FROM <tablename>
WHERE LEFT(<column>, 4) = "<4 digits>"
or
SELECT *
FROM <tablename>
WHERE <column> LIKE "<4 digits>%"
or in the PHP side :
if (strpos($column,'<4 digit>') !== false) {
echo 'true';
}
Use this, to get substring
SELECT aut_name,
RIGHT(aut_name,7)
FROM author
WHERE country='UK';
See more at: http://www.w3resource.com/mysql/string-functions/mysql-right-function.php#sthash.xKNwZeki.dpuf
I suggest this solution:
$variableWhereYoustoreTheFourDigits="1234"; //Use whatever you have in your code to set the value.
$result =$mysqli->query("SELECT number FROM yourtable where number LIKE \"$variableWhereYoustoreTheFourDigits%\");
I've a database with lon and lat geo location data.
Both are saved as float / decimal attribute in the mysql table.
Now I want to compare this stuff like:
(u.user_location_lat <= ".$lat_max." AND u.user_location_lat >= ".$lat_min.") AND
(u.user_location_long <= ".$long_max." AND u.user_location_long >=".$long_min.")
But it does not show any result (and it should!) - but also no error.
How to EASILY solve this (I actually don't want to work with spatial indexes - at least I do not understand how to do)?
Thanks.
I recommend you verify what that statement looks like, after you do the variable substitution.
That is, echo or vardump the contents of the variable containing the SQL text, before you prepare/execute the SQL statement.
There doesn't appear to be anything wrong with the form of the predicates. (These could be written using equivalent BETWEEN comparators, but it's not a problem what you have written.)
It's possible you have the min and max values swapped, or have the longitude and latitude swapped. If that's not the issue, then I suspect that the variables being substituted may be represented in scientific notation, rather than as decimal values.
e.g. the SQL text gets generated
... u.lat <= 1.241E+2 ...
rather than
... u.lat <= 124.1 ...
In the former case, MySQL is going to evaluate that literal as decimal value of 1.241.
(There's a corner case issue when the bounding box crosses the +180/-180 boundary, but I don't see that's likely a problem for most of your values, that's going to be an exceptional case, which you would probably need to setup special test case to actually have happen.)
In order to debug this, you need the actual SQL text that's being sent to the database to be prepared/executed.
(There's not enough information in your question to identify the actual problem.)
Q: How do I get the actual SQL text?
A: Construct your SQL statement as a string into a variable; and then var_dump that variable for debugging:
$sqltext = "SELECT ... WHERE u.lat <= ". $lat_max . " AND u.lat ... ";
var_dump($sqltext);
$stmt = mysqli_prepare($db, $sqltext);
I have two, hopefully basic number questions.
First, I am using the decimal data type on MySQL to show data like speed or height set to one decimal place like this decimal(4,1) My problem is that for numbers with no dp it is still showing .0 - What I get is '309.0' but what I want is '309'. What do I need to change to hide the '.0'?
Second I have an integer data type showing fixed numbers. Many of the numbers are 0 zero but these are getting treated as null and not displaying. How do I force the 0's to display? (I can't make table changes for this because other columns do have zero's that are null values. It is only this one column that needs zeros to display).
For both of these problems PHP is being used to display the results.
EDIT: code I'm using to display results. the top one needs to not show .0 the bottom one needs to show a zero.
Length:</b> %sft' . PHP_EOL, $row2['length'])
Inversions:</b> %s' . PHP_EOL, $row2['inversions'])
I believe a sneaky trick is if you add 0 to the end of your number, it removes the .0000 etc.
example:
$number = 150.00
$number = $number + 0; //should echo 150
$other_number = 150.500;
$other_number += 0; //should echo 150.5
As for the other, you can simply concatenate the zeros since no calculations seem to be needed
To check for the trailing zero, you could use the following to make sure that the float and integer values are the same:
$num = (floatval($num)==intval($num)) ? intval($num) : floatval($num);
and then for the null value, you could use coalesce(yourColumn, 0) as yourColumn to either get your column value if not null or return 0 as the value..
I am trying to build a simple web app to keep up with my debt and I want to use the same database table for adding and also subtracting data.
I am converting the input from the input field using a simple php operation to convert it to a negative number:
$sum2 = $sum*-1;
$sum being the input field:
$sum = $_POST['shuma'];
The Idea is, when I input a positive number, my debt grows larger, when I input a negative number, my debt gets smaller, it's a simple idea.
In MySQL database, I am inserting the input into:
decimal(7,2) Default:Null
The problem is, the positive input, even though it's being converted into a negative number, it's not being inserted as negative in MySQL, it inserts it again with a positive number. The problem it's not within PHP because I tested it and even after the form it's submitted and data it's pushed into MySQL, I still can get the negative number shown using the echo in PHP.
Does anyone have any idea how to solve this?
P.S. Maybe I should mention, when I try to insert negative directly from phpmyadmin it works, it accepts the negative number in the same field.
Thank you.
change you field type to DECIMAL (10,2) . Field length defination is on you. Define length according to your requirement.
In this case negative value will be inserted. If not, then please die(); your query and execute it directly in mysql. Because for another field's problem also negative value not insert in table though the field type is DECIMAL.
Well, I am trying to use the same input field for both, only use a
checkbox, when the box it's checked, it's a negative number, otherwise
it's positive
About that comment.
i.e. you have
<input type="checkbox" name="negative"/>
<input type="text" name="sum" />
<?php
$sum = (int)$_POST['sum'];
...
so you can have, let's say two methods:
function increase($value) {
return query("UPDATE table SET value = value + $value");
}
and
function decrease($value) {
return query("UPDATE table SET value = value - $value");
}
so you are checking:
if(isset($_POST['negative']) {
decrease($sum);
}
else {
increase($sum);
}
However, the queries are just a sample, I just wanted to explain the logic, where you don't need to add the number with negative sign, but you can change the query depends on the checked inputs
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.