Description:
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There's an inconsistency in behaviour between mysqli and PDO_MSYQL in the following SELECT, e.g.,

SELECT TRUNCATE(SUM(aFloatColumn),2) FROM aTable;

Let's say the sum of the column is 42.001.

With PDO_MYSQL, you'll get "42.00".

But with MYSQLI, you'll instead get "42".


Test script:
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<?php
$link = mysqli_connect("localhost", "user", "password", "dbname");

$query = 'CREATE TABLE t (f FLOAT)';
$stmt = mysqli_prepare($link, $query);
mysqli_stmt_execute($stmt);

$query = 'TRUNCATE TABLE t';
$stmt = mysqli_prepare($link, $query);
mysqli_stmt_execute($stmt);

$query = 'INSERT INTO t (f) VALUES (42.001)';
$stmt = mysqli_prepare($link, $query);
mysqli_stmt_execute($stmt);

$query = "SELECT truncate(sum(f), 2) from t";
$stmt = mysqli_prepare($link, $query);
mysqli_stmt_execute($stmt);

mysqli_stmt_bind_result($stmt, $revenue);
while (mysqli_stmt_fetch($stmt)) {
    printf ("%s\n", $revenue);
}

mysqli_stmt_close($stmt);
mysqli_close($link);


Expected result:
----------------
42.00

Actual result:
--------------
42