PDO::sqliteCreateCollation
Registers a User Defined Function for use as a collating function in SQL statements
Description
public bool PDO::sqliteCreateCollation(string $name, callable $callback)
WarningThis function is
EXPERIMENTAL. The behaviour of this function, its name, and
surrounding documentation may change without notice in a future release of PHP.
This function should be used at your own risk.
Parameters
-
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:
int collation(string $string1, string $string2)
Return Values
Returns true on success or false on failure.
Examples
Example #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";
}
?>
The above example will output: