mysqli::prepare
The cryptic "Couldn't fetch mysqli" error message can mean any number of things, including:
1. You're trying to use a database object that you've already closed (as noted by ceo at l-i-e dot com). Reopen your database connection, or find the call to <?php mysqli_close($db); ?> or <?php $db->close(); ?> and remove it.
2. Your MySQLi object has been serialized and unserialized for some reason. Define a wakeup function to re-create your database connection. http://php.net/__wakeup
3. Something besides you closed your mysqli connection (in particular, see http://bugs.php.net/bug.php?id=33772)
4. You mixed OOP and functional calls to the database object. (So, you have <?php $db->query() ?> in the same program as <?php mysqli_query($db) ?>).
mysqli::query
mysqli_query
(PHP 5)
mysqli::query -- mysqli_query — データベース上でクエリを実行する
説明
オブジェクト指向型
手続き型
データベースに対してクエリ query
を実行します。
DML (INSERT、UPDATE あるいは DELETE) 以外のクエリについては、 この関数は mysqli_real_query() に続けて mysqli_use_result() あるいは mysqli_store_result() をコールすることと同等です。
注意:
サーバーの max_allowed_packet よりも長いステートメントを mysqli_query() に渡した場合、 返ってくるエラーコードは MySQL Native Driver (mysqlnd) を使っているか MySQL Client Library (libmysqlclient) を使っているかで異なります。 それぞれ、次のように振る舞います。
Linux 上の mysqlnd では、エラーコード 1153 を返します。 エラーメッセージは "got a packet bigger than max_allowed_packet bytes" です。
Windows 上の mysqlnd では、エラーコード 2006 を返します。 エラーメッセージは "server has gone away" です。
すべてのプラットフォームの libmysqlclient では、エラーコード 2006 を返します。エラーメッセージは "server has gone away" です。
パラメータ
-
link -
手続き型のみ: mysqli_connect() あるいは mysqli_init() が返すリンク ID。
-
query -
クエリ文字列。
クエリ内のデータは 適切にエスケープ. する必要があります。
-
resultmode -
定数
MYSQLI_USE_RESULTあるいはMYSQLI_STORE_RESULTで、望みの挙動を指定します。 デフォルトではMYSQLI_STORE_RESULTを使用します。MYSQLI_USE_RESULT を使用すると、 mysqli_free_result() をコールするまでは それ以降のコールはすべて Commands out of sync エラーを返します。
MYSQLI_ASYNC(mysqlnd で使用可能) を使用すると、クエリを非同期実行できるようになります。 このクエリの結果を取得するには mysqli_poll() を使用します。
返り値
失敗した場合に FALSE を返します。
SELECT, SHOW, DESCRIBE あるいは
EXPLAIN が成功した場合は、 mysqli_query()
は mysqli_result オブジェクトを返します。それ以外のクエリが成功した場合は、
mysqli_query() は TRUE を返します。
変更履歴
| バージョン | 説明 |
|---|---|
| 5.3.0 | 非同期クエリ機能が追加されました。 |
例
例1 mysqli::query() の例
オブジェクト指向型
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* 接続状況をチェックします */
if ($mysqli->connect_errno) {
printf("Connect failed: %s\n", $mysqli->connect_error);
exit();
}
/* テーブルを作成します。これは結果セットを返しません */
if ($mysqli->query("CREATE TEMPORARY TABLE myCity LIKE City") === TRUE) {
printf("Table myCity successfully created.\n");
}
/* Select クエリを実行します。これは結果セットを返します */
if ($result = $mysqli->query("SELECT Name FROM City LIMIT 10")) {
printf("Select returned %d rows.\n", $result->num_rows);
/* 結果セットを開放します */
$result->close();
}
/* 大量のデータを取得する必要がある場合は MYSQLI_USE_RESULT を使用します */
if ($result = $mysqli->query("SELECT * FROM City", MYSQLI_USE_RESULT)) {
/* この結果セットが閉じられるまで、サーバーとやりとりする関数は
一切実行できないことに注意しましょう。関数をコールすると、
'out of sync' エラーが発生します */
if (!$mysqli->query("SET @a:='this will not work'")) {
printf("Error: %s\n", $mysqli->error);
}
$result->close();
}
$mysqli->close();
?>
手続き型
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* 接続状況をチェックします */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* テーブルを作成します。これは結果セットを返しません */
if (mysqli_query($link, "CREATE TEMPORARY TABLE myCity LIKE City") === TRUE) {
printf("Table myCity successfully created.\n");
}
/* Select クエリを実行します。これは結果セットを返します */
if ($result = mysqli_query($link, "SELECT Name FROM City LIMIT 10")) {
printf("Select returned %d rows.\n", mysqli_num_rows($result));
/* 結果セットを開放します */
mysqli_free_result($result);
}
/* 大量のデータを取得する必要がある場合は MYSQLI_USE_RESULT を使用します */
if ($result = mysqli_query($link, "SELECT * FROM City", MYSQLI_USE_RESULT)) {
/* この結果セットが閉じられるまで、サーバーとやりとりする関数は
一切実行できないことに注意しましょう。関数をコールすると、
'out of sync' エラーが発生します */
if (!mysqli_query($link, "SET @a:='this will not work'")) {
printf("Error: %s\n", mysqli_error($link));
}
mysqli_free_result($result);
}
mysqli_close($link);
?>
上の例の出力は以下となります。
Table myCity successfully created. Select returned 10 rows. Error: Commands out of sync; You can't run this command now
参考
- mysqli_real_query() - SQL クエリを実行する
- mysqli_multi_query() - データベース上でクエリを実行する
- mysqli_free_result() - 結果に関連付けられたメモリを開放する
add a note
User Contributed Notes
mysqli::query - [16 notes]
theyranos at gmail dot com ¶
2 years ago
marcus at synchromedia dot co dot uk ¶
2 years ago
The exact type returned by a successful query is mysqli_result.
thomas dekker ¶
2 years ago
Building inserts can be annoying. This helper function inserts an array into a table, using the key names as column names:
<?php
private function store_array (&$data, $table, $mysqli)
{
$cols = implode(',', array_keys($data));
foreach (array_values($data) as $value)
{
isset($vals) ? $vals .= ',' : $vals = '';
$vals .= '\''.$this->mysql->real_escape_string($value).'\'';
}
$mysqli->real_query('INSERT INTO '.$table.' ('.$cols.') VALUES ('.$vals.')');
}
?>
Adapt it to your specific needs.
registrations at jdfoxmicro dot com ¶
2 years ago
I like to save the query itself in a log file, so that I don't have to worry about whether the site is live.
For example, I might have a global function:
<?php
function UpdateLog ( $string , $logfile ) {
$fh = fopen ( $logfile , 'a' );
$fwrite ( $fh , strftime ('%F %T %z')." ".$string."\n";
fclose ( $fh );
}
?>
Then in my mysql function error trapper, something like this:
<?php
$error_msg = "Database error in [page].php / ";
$error_msg .= mysqli_error ( $link )." / ";
$error_msg .= $query;
UpdateLog ( $error_msg , DB_ERROR_LOG_FILE );
?>
I also include the remote IP, user agent, etc., but I left it out of these code samples. And have it e-mail me when an error is caught, too.
Jeff
NUNTIUS ¶
5 years ago
This may or may not be obvious to people but perhaps it will help someone.
When running joins in SQL you may encounter a problem if you are trying to pull two columns with the same name. mysqli returns the last in the query when called by name. So to get what you need you can use an alias.
Below I am trying to join a user id with a user role. in the first table (tbl_usr), role is a number and in the second is a text name (tbl_memrole is a lookup table). If I call them both as role I get the text as it is the last "role" in the query. If I use an alias then I get both as desired as shown below.
<?php
$sql = "SELECT a.uid, a.role AS roleid, b.role,
FROM tbl_usr a
INNER JOIN tbl_memrole b
ON a.role = b.id
";
if ($result = $mysqli->query($sql)) {
while($obj = $result->fetch_object()){
$line.=$obj->uid;
$line.=$obj->role;
$line.=$obj->roleid;
}
}
$result->close();
unset($obj);
unset($sql);
unset($query);
?>
In this situation I guess I could have just renamed the role column in the first table roleid and that would have taken care of it, but it was a learning experience.
antiriad at gmail dot com ¶
6 years ago
this is a variant of mysqli_query that returns output parameters as a rowset.
<?php
function mysqli_exec($link, $command)
{
$select = '';
$i2 = 0;
while (true)
{
$i1 = strpos($command, '@', $i2);
if ($i1 === false)
break;
$field = '';
$i2 = $i1 + 1;
while ($i2 < strlen($command) &&
($command[$i2] >= '0' && $command[$i2] <= '9') ||
($command[$i2] >= 'A' && $command[$i2] <= 'Z') ||
($command[$i2] >= 'a' && $command[$i2] <= 'z') ||
($command[$i2] == '_'))
$i2++;
$field = substr($command, $i1 + 1, $i2 - $i1 - 1);
if (strlen($select) == 0)
$select = "select @{$field} as $field";
else
$select = $select . ", @{$field} as $field";
}
if (strlen($select) > 0)
{
mysqli_query($link, $command);
return mysqli_query($link, $select);
}
else
return mysqli_query($link, $command);
}
?>
an example:
<?php
$link = mysqli_connect('localhost', 'myusr', 'mypass') or die ('Error connecting to mysql: ' . mysqli_error($link));
mysqli_select_db($link, 'clips');
$user_name = 'test';
$result = mysqli_exec($link, "call do_user_login('$user_name', @session_id, @msg)");
while ($row = mysqli_fetch_assoc($result))
{
echo "session_id : {$row['session_id']} <br>";
echo "msg : {$row['msg']} <br>";
}
?>
info at ff dot net ¶
7 years ago
Calling Stored Procedures
Beeners' note/example will not work. Use mysqli_multi_query() to call a Stored Procedure. SP's have a second result-set which contains the status: 'OK' or 'ERR'. Using mysqli_query will not work, as there are multiple results.
<?php
$sQuery="CALL SomeSP('params')";
if(!mysqli_multi_query($sqlLink,$sQuery)) {
// your error handler
}
$sqlResult=mysqli_store_result($sqlLink);
if(mysqli_more_results($this->sqlLink))//Catch 'OK'/'ERR'
while(mysqli_next_result($this->sqlLink));
?>
You will have to rewrite/expand this a bit for more usability of course, but it's just an example.
hunreal at gmail dot com ¶
8 years ago
Use difference collation/character for connect, result.
You can set the collation before your query.
E.g. want to set the collation to utf8_general_ci
you can send the query "SET NAMES 'utf8'" first
<?php
$mysqli=new mysqli('localhost', 'root', 'password', 'test');
$mysqli->query("SET NAMES 'utf8'");
$q=$mysqli->query("select * from test");
while($r=$q->fetch_assoc()) {
print_r($r);
}
?>
There are many variables about character settings.
By running sql command, SHOW VARIABLES LIKE 'char%';
There are some variables control the character usage.
character_set_client
character_set_connection
character_set_database
character_set_results
character_set_server
character_set_system
Also SET NAMES can repalce with one or some settings like SET character_set_results='utf8';
ceo at l-i-e dot com ¶
4 years ago
Translation:
"Couldn't fetch mysqli"
You closed your connection and are trying to use it again.
It has taken me DAYS to figure out what this obscure error message means...
Igor ¶
4 years ago
mysqli::query() can only execute one SQL statement.
Use mysqli::multi_query() when you want to run multiple SQL statements within one query.
petrus.jvr ¶
2 years ago
When calling multiple stored procedures, you can run into the following error: "Commands out of sync; you can't run this command now".
This can happen even when using the close() function on the result object between calls.
To fix the problem, remember to call the next_result() function on the mysqli object after each stored procedure call. See example below:
<?php
// New Connection
$db = new mysqli('localhost','user','pass','database');
// Check for errors
if(mysqli_connect_errno()){
echo mysqli_connect_error();
}
// 1st Query
$result = $db->query("call getUsers()");
if($result){
// Cycle through results
while ($row = $result->fetch_object()){
$user_arr[] = $row;
}
// Free result set
$result->close();
$db->next_result();
}
// 2nd Query
$result = $db->query("call getGroups()");
if($result){
// Cycle through results
while ($row = $result->fetch_object()){
$group_arr[] = $row;
}
// Free result set
$result->close();
$db->next_result();
}
else echo($db->error);
// Close connection
$db->close();
?>
jcwebb at dicoe dot com ¶
6 years ago
When building apps, i like to see the whole statement when if fails.
<?php
$q="SELECT somecolumn FROM sometable"; //some instruction
$r=mysqli_query($DBlink,$q) or die(mysqli_error($DBlink)." Q=".$q);
?>
If theres an error (like my numerous typing mistakes) this shows the entire instruction.
Good for development (not so good on production servers - simply find and replace when finished: $r=mysqli_query($DBlink,$q); )
Hope it helps. Jon
Beeners ¶
7 years ago
Stored Procedures.
Use mysqli_query to call a stored procedure that returns a result set.
Here is a short example:
<?php
$mysqli = new mysqli(DBURI,DBUSER,DBPASS,DBNAME);
if (mysqli_connect_errno())
{
printf("Connection failed: %s\n", mysqli_connect_error());
exit();
}
$SQL = "CALL my_procedure($something)";
if ( ($result = $mysqli->query($SQL))===false )
{
printf("Invalid query: %s\nWhole query: %s\n", $mysqli->error, $SQL);
exit();
}
while ($myrow = $result->fetch_array(MYSQLI_ASSOC))
{
$aValue[]=$myrow["a"];
$bValue[]=$myrow["b"];
}
$result->close();
$mysqli->close();
?>
I hope this saves someone some time.
andrey at php dot net ¶
7 years ago
WARNING: This function was buggy on 64bit machines till 5.0.5. Affected versions 5.0.0-5.0.4. The problem appears when a value for the third parameter is passed - this will lead to instant FALSE returned by the function. Therefore if you need to use unbuffered query don't use this function with the aforementioned versions but you mysqli_real_query() and mysqli_use_result().
If you have the rights to patch you PHP installation the fix is easy:
In file ext/mysqli/myslqi_nonapi.c, function PHP_FUNCTION(mysqli_query)
change
unsigned int resultmode=0;
to
unsigned long resultmode=0;
Thanks!
Charlie Chan ¶
2 years ago
You can create similar generic statements for updates and deletes.
<?php
function genericUpdate($tablename, $opts, $where) {
$opts = cleanseArray($opts);
$keys = array_keys($opts);
$vals = array_values($opts);
$setString;
$whereString;
for ($i = 0; $i < count($keys); $i++) {
if (in_array($keys[$i], $where)) {
if (!isset($whereString))
$whereString = $keys[$i]." = '".$vals[$i]."'";
else
$whereString = $whereString." AND ".$keys[$i]." = '".$vals[$i]."'";
} else {
if (!isset($setString))
$setString = $keys[$i]." = '".$vals[$i]."'";
else
$setString = $setString.", ".$keys[$i]." = '".$vals[$i]."'";
}
}
$sql = "UPDATE $tablename SET ".$setString." WHERE ".$whereString;
logDebug("SQL TO Update KEYS: ".$sql);
return dbQuery($sql);
}
function genericDelete($tablename, $opts) {
$opts = cleanseArray($opts);
$keys = array_keys($opts);
$vals = array_values($opts);
$whereString;
for ($i = 0; $i < count($keys); $i++) {
if ($i == (count($keys) - 1))
$whereString = $whereString.$keys[$i]." = '".$vals[$i]."'";
else
$whereString = $whereString.$keys[$i]." = '".$vals[$i]."' AND ";
}
$sql = "DELETE FROM ". $tablename . " WHERE " . $whereString;
logDebug("SQL TO DELETE KEYS: ".$sql);
return dbQuery($sql);
}
?>
Just be sure that you cleanse your arrays before input into DB.
<?php
function cleansePureString($str, $char = '\\')
{
///[^a-zA-Z0-9\s]/ NON ALPHA
$cleansed = preg_replace("/[%_'\"]/", '', $str); //_, % and '
//logDebug("CLEANSED VAL: ".$cleansed);
return $cleansed;
}
function cleanseArray($opts) {
$cleansedArray = array();
$keys = array_keys($opts);
$vals = array_values($opts);
for ($i = 0; $i < count($keys); $i++) {
$newKey = cleansePureString($keys[$i],"'");
$newVal = cleansePureString($vals[$i],"'");
$cleansedArray[$newKey] = $newVal;
}
return $cleansedArray;
}
?>
blinki bill, argodak at yahoo dot com ¶
13 days ago
Recently I had puzzling problem when performing DML queries, update in particular, each time a update query is called and then there are some more queries to follow this error will show on the page and go in the error_log:
"Fatal error: Exception thrown without a stack frame in Unknown on line 0"
The strange thing is that all queries go through just fine so it didn't make much sense:
$update = mysqli_query($connection, $query_string);
if(!$update){
echo 'Houston we have a problem '.mysqli_error($connection);
exit;
}
In the above example "$update" is "true", mysqli_error() is empty and of course the update operation goes through, however the nasty super cryptic error appears on the page.
What makes even less sense to me is how I fixed it - just called "mysqli_free_result" after the update query and the problem was gone, however because mysqli_free_result is not supposed to be called after DML queries (to free what, a boolean? lol) it needs to be wrapped in a try catch block:
try{
mysqli_free_result($update);
}catch (Exception $e){
//do nothing
}
So, I don't know why but it seems that when DML queries are responsible for:
"Fatal error: Exception thrown without a stack frame in Unknown on line 0"
calling "mysqli_free_result" after the query seems to be fixing the issue