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    PDO::sqliteCreateCollation

    (PHP 5 >= 5.3.11, PHP 7, PHP 8)

    PDO::sqliteCreateCollation — Registers a User Defined Function for use as a collating function in SQL statements

    说明

    public PDO::sqliteCreateCollation(string $name, callable $callback): bool
    警告

    此函数是实验性的。此函数的表象，包括名称及其相关文档都可能在未来的 PHP 发布版本中未通知就被修改。使用本函数风险自担。

    参数

    name

    Name of the SQL collating function to be created or redefined.

    callback

    The name of a PHP function or user-defined function to apply as a callback, defining the behavior of the collation. It should accept two strings and return as strcmp() does, i.e. it should return -1, 1, or 0 if the first string sorts before, sorts after, or is equal to the second.

    This function need to be defined as:

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

    返回值

    成功时返回 true， 或者在失败时返回 false。

    示例

    示例 #1 PDO::sqliteCreateCollation() example

    <?php
    $db     = new PDO('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";
    }
    ?>

    以上示例会输出：

    a1
a10
a2

a1
a2
a10

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