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    Pdo\Sqlite::createCollation

    (PHP 8 >= 8.4.0)

    Pdo\Sqlite::createCollation — Registers a user-defined function for use as a collating function in SQL statements

    説明

    public Pdo\Sqlite::createCollation(string $name, callable $callback): bool

    This method is similar to Pdo\Sqlite::createFunction() except that it registers functions that are used to collate strings.

    パラメータ

    name
    Name of the SQL collating function to be created or redefined.
    callback
    Callback function that defines the behaviour of a collation. It must accept two strings and return -1, 0, or 1 if the first string sorts before, sorts identically, or sorts after the second string respectively. An internal function that behaves like this is strcmp().

    This function need to be defined as:

    collation(string $string1, string $string2): int

    戻り値

    成功した場合に true を、失敗した場合に false を返します。

    例

    例1 Pdo\Sqlite::createCollation() example

    <?php
    $db     = new Pdo\Sqlite('sqlite::memory:');
    $db->exec("CREATE TABLE test (col1 string)");
    $db->exec("INSERT INTO test VALUES ('a1')");
    $db->exec("INSERT INTO test VALUES ('a10')");
    $db->exec("INSERT INTO test VALUES ('a2')");

    $db->sqliteCreateCollation('NATURAL_CMP', 'strnatcmp');
    foreach (    $db->query("SELECT col1 FROM test ORDER BY col1") as $row) {
    echo     $row['col1'] . "\n";
    }
    echo     "\n";
    foreach (    $db->query("SELECT col1 FROM test ORDER BY col1 COLLATE NATURAL_CMP") as $row) {
    echo     $row['col1'] . "\n";
    }
    ?>

    上の例の出力は以下となります。

    a1
a10
a2

a1
a2
a10

    参考

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