SQLite3::createCollation()
(PHP 5 >= 5.3.11, PHP 7)
Registers a PHP function for use as an SQL collating function
说明
public SQLite3::createCollation(string $name,callable $callback): bool
Registers a PHP function or user-defined function for use as a collating function within SQL statements.
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 values 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(mixed $value1, mixed $value2): int
返回值
成功时返回TRUE，或者在失败时返回FALSE。
范例
SQLite3::createCollation() example
Register the PHP function strnatcmp() as a collating sequence in the SQLite3 database.
<?php
$db = new SQLite3(":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->createCollation('NATURAL_CMP', 'strnatcmp');
$defaultSort = $db->query("SELECT col1 FROM test ORDER BY col1");
$naturalSort = $db->query("SELECT col1 FROM test ORDER BY col1 COLLATE NATURAL_CMP");
echo "default:\n";
while ($row = $defaultSort->fetchArray()){
echo $row['col1'], "\n";
}
echo "\nnatural:\n";
while ($row = $naturalSort->fetchArray()){
echo $row['col1'], "\n";
}
$db->close();
?>
以上例程会输出：
default: a1 a10 a2 natural: a1 a2 a10
参见
- The SQLite collation documentation:» http://sqlite.org/datatype3.html#collation