Radionica programiranje 39.

Potrebno predznanje.
SQL upit: Koliko je svaki polaznik u postocima od ukupne uplate dao za knjige
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<?php
$link = mysqli_connect("localhost", "root", "", "mariva");
$sql = "SELECT id_racuna,
Concat(Format((Sum(knjige)/Sum(iznos_racuna)*100), 2, 'de_DE'),'%')
AS postotakKnjige
FROM racuni
GROUP BY id_racuna";
$result = mysqli_query($link, $sql);
While ($row = mysqli_fetch_assoc($result))
{
print $row["id_racuna"] . " " . $row["postotakKnjige"] . "<br>";
}
?>

SQL upit: Crosstab
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There is no MySQL (or any other decent RDBMS for that matter) equivalent of the Access operator TRANSFORM, which automatically produces a dynamic number of columns from the data.