/*here is a nice function for converting a mysql result row set into a 2d array, a time saver if need small data from several rows, saves you from having to do Alot of queries... would be nice to have this built into PHP future versions :) */
// simple example query
$r=mysql_query("select user,id,ip from accounts limit 10");
//starts the for loop, using mysql_num_rows() to count total
//amount of rows returned by $r
for($i=0; $i<mysql_num_rows($r); $i++){
//advances the row in the mysql resource $r
mysql_data_seek($r,$i);
//assigns the array keys, $users[row][field]
$users[$i]=mysql_fetch_row($r);
}
//simple, hope someone can use it :)
// -Kenneth Nash
mysql_data_seek
(PHP 4, PHP 5)
mysql_data_seek — 내부 결과 포인터를 이동
설명
bool mysql_data_seek
( resource
$result
, int $row_number
)mysql_data_seek()는 result에 지정한 MySQL 결과의 내부 행 포인터를 지정한 행 번호로 옮깁니다. 다음으로 mysql_fetch_assoc() 등의 MySQL 페치 함수를 호출하면, 그 행이 반환됩니다.
row_number는 0부터 시작합니다.
row_number는 0부터
mysql_num_rows() - 1까지의 값을 가질 수 있습니다. 그러나
결과셋이 비어 있고(mysql_num_rows() == 0), 0행을
탐색하면 E_WARNING을
발생하며 실패하고 mysql_data_seek()는 FALSE를
반환합니다.
반환값
성공 시 TRUE를, 실패 시 FALSE를 반환합니다.
예제
Example #1 mysql_data_seek() 예제
<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
$db_selected = mysql_select_db('sample_db');
if (!$db_selected) {
die('Could not select database: ' . mysql_error());
}
$query = 'SELECT last_name, first_name FROM friends';
$result = mysql_query($query);
if (!$result) {
die('Query failed: ' . mysql_error());
}
/* fetch rows in reverse order */
for ($i = mysql_num_rows($result) - 1; $i >= 0; $i--) {
if (!mysql_data_seek($result, $i)) {
echo "Cannot seek to row $i: " . mysql_error() . "\n";
continue;
}
if (!($row = mysql_fetch_assoc($result))) {
continue;
}
echo $row['last_name'] . ' ' . $row['first_name'] . "<br />\n";
}
mysql_free_result($result);
?>
주의
Note:
mysql_data_seek() 함수는 mysql_query()와 함께 사용할 경우에는 사용할 수 있으나 , mysql_unbuffered_query()와는 함께 사용할 수 없다.
참고
- mysql_query() - MySQL 질의를 전송
- mysql_num_rows() - 결과로부터 행의 개수를 반환
- mysql_fetch_row() - 숫자 색인 배열로 결과를 반환
- mysql_fetch_assoc() - 연관 배열로 결과 행을 반환
- mysql_fetch_array() - 연관 색인 및 숫자 색인으로 된 배열로 결과 행을 반환
- mysql_fetch_object() - 객체형으로 결과 행을 인출
add a note
User Contributed Notes 6 notes
kennethnash1134 at yahoo dot com ¶
20 years ago
saeed at photobookworldwide dot com ¶
12 years ago
Here, you can find the current pointer of selected row easily:
<?php
//selected row with id=4
$id = "4";
$result = mysql_query("select * from jos_components");
$num = mysql_num_rows($result);
for($i=0;$i<$num;$i++){
mysql_data_seek($result,$i);
$row = mysql_fetch_assoc($result);
if($row['id'] == $id){
$pointer = $i;
}
}
// current pointer for selected row
echo $pointer;
?>
arturo_b at hotmail dot com ¶
19 years ago
hello, this script would be easy to understand for those that are novice in php whose want to understand about this function:
the table "user" have 2 columns "id" and "name".
"user" content:
position 0: "id"=195342481 "name"='Arthur'
position 1: "id"=179154675 "name"='John'
>>position 2<<: "id"=157761949 "name"='April' >>third row<<
position 3: "id"=124492684 "name"='Tammy'
position 4: "id"=191346457 "name"='Mike'
<?php
mysql_connect("localhost", "root")
mysql_select_db("test");
$sql = mysql_query("select * from user");
mysql_data_seek($sql, 2);
echo "<table border=1>";
while ($row = mysql_fetch_row($sql)){
echo "<tr><td>$row[0]</td><td>$row[1]</td></tr>";
}
echo "</tabla>";
?>
explanation:
mysql_data_seek move internal result pointer to the third row of table user. Thus mysql_fetch_row will begin by aprils row.
b.steinbrink at g m x dot de ¶
19 years ago
to kennethnash1134 at yahoo dot com
your loop can be done like this as well and i guess this is faster:
$r=mysql_query("select user,id,ip from accounts limit 10");
unset($users); // Just to be sure
while($users[] = mysql_fetch_row);
array_pop($users); // Drop the last entry which is FALSE
Daniel ¶
15 years ago
Here is a simple function to "peek" at the position of the internal pointer in a query result:
<?php
function mysql_pointer_position($result_set) {
$num_rows = mysql_num_rows($result_set);
$i = 0;
while($result = mysql_fetch_array($result_set)) {
$i++;
}
$pointer_position = $num_rows - $i;
//Return pointer to original position
if($pointer_position <= $num_rows - 1) {
mysql_data_seek($result_set, $pointer_position);
}
return $pointer_position;
}
?>
Anonymous ¶
17 years ago
A helpful note about the 'resource' data type.
Since the 'resource' variable is pointing to a row in a result set at any given time, you can think of it as being passed to this function by reference every time you pass it or assign it to a variable.
<?
$sql = "SELECT * from <table>";
$result = mysql_query($sql);
$temp_result = $result;
while ($row = mysql_fetch_assoc($temp_result)) {
// do stuff with $row
}
while ($row = mysql_fetch_assoc($result)) {
// This code will never run because the 'resource' variable is pointing past the end of the result set,
// even though it was *not* assigned by reference to $result2.
}
?>
Therefore, the following snipits are functionally identical:
<?
// Start snipit 1
$sql = "SELECT * from <table>";
$result = mysql_query($sql);
while ($row = mysql_fetch_assoc($result)) {
// do stuff with $row
}
mysql_data_seek($result, 0);
while ($row = mysql_fetch_assoc($result)) {
// do other stuff with $row
}
// Start snipit 2
$sql = "SELECT * from <table>";
$result = mysql_query($sql);
$temp_result = $result;
while ($row = mysql_fetch_assoc($temp_result)) {
// do stuff with $row
}
mysql_data_seek($result, 0);
while ($row = mysql_fetch_assoc($temp_result)) {
// do other stuff with $row
}
?>
