PHP Pdo Select Query Returns Double Values

PHP PDO Select query returns double values

Set the default fetch mode like so

$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_OBJ); 

Or

$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC); 

before running the fetch

$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
foreach($result as $row) {
    array_push($result_array, $row);
}

Or replace with a one liners using fetchAll() and use prepared and parameterized statements as well to mitigate against SQL Injection Attack

$query = "SELECT datum, tijd, zone,lucht, temperatuur 
            FROM waarden 
            WHERE datum = :datum";
$result->prepare($query);

$result->execute([':datum'=>$waarde]);

$result_array = $result->fetchAll(PDO::FETCH_ASSOC);

The parameter to fetchAll(PDO::FETCH_ASSOC) controls how results will be returned.

PHP PDO execute() returning duplicate results

Solved by checking with someone better at databases than myself...

I foolishly named the columns as integer values.

So, what appeared as "duplicate values" was just the fact that the column number and the column name were the same!

In conclusion, I am bad at database structure.

PDO prepared statement fetch() returning double results

You should say to PDO, that you want only an associative array or a numbered array:

while ($rows_get_rows = $result_get_rows->fetch(PDO::FETCH_ASSOC)) 

to get an associative array or

while ($rows_get_rows = $result_get_rows->fetch(PDO::FETCH_NUM)) 

to get an array indexed by the column number

from PDOStatement::fetch

fetch_style

Controls how the next row will be returned to the caller.
This value must be one of the PDO::FETCH_* constants, defaulting to
value of PDO::ATTR_DEFAULT_FETCH_MODE (which defaults to
PDO::FETCH_BOTH).

PDO::FETCH_ASSOC: returns an array indexed by column name as returned
in your result set

PDO::FETCH_BOTH (default): returns an array indexed by both column
name and 0-indexed column number as returned in your result set

PDO returning incorrect, but duplicate, data. Key's not in database.

It's not duplicates, it's just the current FETCH_MODE you're using. To get as associative keys only you need to specify as such; by default it fetches as both.

Use like so:

$query->fetchAll(PDO::FETCH_NUM); // to fetch with numeric indexes
$query->fetchAll(PDO::FETCH_ASSOC); // to fetch with associative indexes

fetchAll docs

fetch docs

sql PDO fetchall duplicate object keys?

You have to specify fetching mode

$q->fetchAll(PDO::FETCH_ASSOC);

PDO: Remove duplicates of the query's results

The first argument of your fetchAll call schould be PDO::FETCH_ASSOC

See http://php.net/manual/en/pdostatement.fetch.php

PHP PDO query returns inaccurate value for FLOAT fields

As documented under Floating-Point Types (Approximate Value) - FLOAT, DOUBLE:

MySQL performs rounding when storing values, so if you insert 999.00009 into a FLOAT(7,4) column, the approximate result is 999.0001.

Because floating-point values are approximate and not stored as exact values, attempts to treat them as exact in comparisons may lead to problems. They are also subject to platform or implementation dependencies. For more information, see Section C.5.5.8, “Problems with Floating-Point Values”

For maximum portability, code requiring storage of approximate numeric data values should use FLOAT or DOUBLE PRECISION with no specification of precision or number of digits.

Therefore, upon inserting 1.8 into your database, MySQL rounded the literal to 001.8000 and encoded the closest approximation to that number in binary32 format: i.e. 0x3FE66666, whose bits signify:

Sign           : 0b0

Biased exponent: 0b01111111
               =   127 (representation includes bias of +127, therefore exp = 0)

Significand    : 0b[1.]11001100110011001100110
                    ^ hidden bit, not stored in binary representation
               =   [1.]7999999523162841796875

This equates to:

 (-1)^0 * 1.7999999523162841796875 * 2^0
=         1.7999999523162841796875

This is the value that is returned by MySQL to the client. It would appear that AdoDB then inspected the column's datatype and rounded the result accordingly, whereas PDO does not.

If you want exact values, you should use a fixed point datatype, such as DECIMAL.

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