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# dbx_compare

(PHP 4 >= 4.1.0, PHP 5)

dbx_compare -- Compare two rows for sorting purposes

## Description

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

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

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`.

示範 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);
?>`

See also dbx_sort().

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