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。

范例

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";
}
?>

以上例程会输出：

a1
a10
a2

a1
a2
a10