Compare two rows for sorting purposes

说明

int dbx_compare ( array $row_a , array $row_b , string $column_key [, int $flags ] )

dbx_compare() is a helper function for dbx_sort() to ease the make and use of the custom sorting function.

参数

row_a

First row

row_b

Second row

column_key

The compared column

flags

The flags can be set to specify comparison direction:

DBX_CMP_ASC - ascending order
DBX_CMP_DESC - descending order

and the preferred comparison type:

DBX_CMP_NATIVE - no type conversion
DBX_CMP_TEXT - compare items as strings
DBX_CMP_NUMBER - compare items numerically

One of the direction and one of the type constant can be combined with bitwise OR operator (|). The default value for the flags parameter is DBX_CMP_ASC | DBX_CMP_NATIVE.

返回值

Returns 0 if the row_a[$column_key] is equal to row_b[$column_key], and 1 or -1 if the former is greater or is smaller than the latter one, respectively, or vice versa if the flag is set to DBX_CMP_DESC.

范例

Example#1 dbx_compare() example


<?php
function user_re_order($a, $b) 
{
    $rv = dbx_compare($a, $b, "parentid", DBX_CMP_DESC);
    if (!$rv) {
        $rv = dbx_compare($a, $b, "id", DBX_CMP_NUMBER);
    }
    return $rv;
}

$link   = dbx_connect(DBX_ODBC, "", "db", "username", "password")
    or die("Could not connect");

$result = dbx_query($link, "SELECT id, parentid, description FROM table ORDER BY id");
    // data in $result is now ordered by id

dbx_sort($result, "user_re_order");
    // date in $result is now ordered by parentid (descending), then by id

dbx_close($link);
?>

参见

dbx_sort()