Mysqli query что возвращает

mysqli_query

For non-DML queries (not INSERT, UPDATE or DELETE), this function is similar to calling mysqli_real_query followed by either mysqli_use_result or mysqli_store_result .

• mysqlnd on Linux returns an error code of 1153. The error message means got a packet bigger than max_allowed_packet bytes .

• mysqlnd on Windows returns an error code 2006. This error message means server has gone away .

• libmysqlclient on all platforms returns an error code 2006. This error message means server has gone away .

Parameters

Procedural style only: A link identifier returned by mysqli_connect or mysqli_init

The query string.

Data inside the query should be properly escaped.

Either the constant MYSQLI_USE_RESULT or MYSQLI_STORE_RESULT depending on the desired behavior. By default, MYSQLI_STORE_RESULT is used.

If you use MYSQLI_USE_RESULT all subsequent calls will return error Commands out of sync unless you call mysqli_free_result

With MYSQLI_ASYNC (available with mysqlnd), it is possible to perform query asynchronously. mysqli_poll is then used to get results from such queries.

Return Values

Returns FALSE on failure. For successful SELECT, SHOW, DESCRIBE or EXPLAIN queries mysqli_query will return a mysqli_result object. For other successful queries mysqli_query will return TRUE .

Changelog

Examples

Example #1 mysqli::query example

Object oriented style

<?php
$mysqli = new mysqli ( «localhost» , «my_user» , «my_password» , «world» );

/* check connection */
if ( $mysqli -> connect_errno ) <
printf ( «Connect failed: %s\n» , $mysqli -> connect_error );
exit();
>

/* Create table doesn’t return a resultset */
if ( $mysqli -> query ( «CREATE TEMPORARY TABLE myCity LIKE City» ) === TRUE ) <
printf ( «Table myCity successfully created.\n» );
>

/* Select queries return a resultset */
if ( $result = $mysqli -> query ( «SELECT Name FROM City LIMIT 10» )) <
printf ( «Select returned %d rows.\n» , $result -> num_rows );

/* free result set */
$result -> close ();
>

/* If we have to retrieve large amount of data we use MYSQLI_USE_RESULT */
if ( $result = $mysqli -> query ( «SELECT * FROM City» , MYSQLI_USE_RESULT )) <

/* Note, that we can’t execute any functions which interact with the
server until result set was closed. All calls will return an
‘out of sync’ error */
if (! $mysqli -> query ( «SET @a:=’this will not work'» )) <
printf ( «Error: %s\n» , $mysqli -> error );
>
$result -> close ();
>

<?php
$link = mysqli_connect ( «localhost» , «my_user» , «my_password» , «world» );

/* check connection */
if ( mysqli_connect_errno ()) <
printf ( «Connect failed: %s\n» , mysqli_connect_error ());
exit();
>

/* Create table doesn’t return a resultset */
if ( mysqli_query ( $link , «CREATE TEMPORARY TABLE myCity LIKE City» ) === TRUE ) <
printf ( «Table myCity successfully created.\n» );
>

/* Select queries return a resultset */
if ( $result = mysqli_query ( $link , «SELECT Name FROM City LIMIT 10» )) <
printf ( «Select returned %d rows.\n» , mysqli_num_rows ( $result ));

/* free result set */
mysqli_free_result ( $result );
>

/* If we have to retrieve large amount of data we use MYSQLI_USE_RESULT */
if ( $result = mysqli_query ( $link , «SELECT * FROM City» , MYSQLI_USE_RESULT )) <

/* Note, that we can’t execute any functions which interact with the
server until result set was closed. All calls will return an
‘out of sync’ error */
if (! mysqli_query ( $link , «SET @a:=’this will not work'» )) <
printf ( «Error: %s\n» , mysqli_error ( $link ));
>
mysqli_free_result ( $result );
>

PHP mysqli query() Function

The query() / mysqli_query() function performs a query against a database.

Syntax

Object oriented style:

Procedural style:

Parameter Values

Optional. A constant. Can be one of the following:

• MYSQLI_USE_RESULT (Use this to retrieve large amount of data)
• MYSQLI_STORE_RESULT (This is default)

Technical Details

Example — Procedural style

Perform query against a database:

if (mysqli_connect_errno()) <
echo "Failed to connect to MySQL: " . mysqli_connect_error();
exit();
>

// Perform query
if ($result = mysqli_query($con, "SELECT * FROM Persons")) <
echo "Returned rows are: " . mysqli_num_rows($result);
// Free result set
mysqli_free_result($result);
>

mysqli_query — return values

I am using the PHP function mysqli_query to run a SELECT query.

What does mysqli_query return if the query runs successfully, but the query finds no matches?

3 Answers 3

Returns FALSE on failure. For successful SELECT, SHOW, DESCRIBE or EXPLAIN queries mysqli_query() will return a mysqli_result object. For other successful queries mysqli_query() will return TRUE.

A query that runs but returns no results is still considered a «successful query», since the query did run in the database and an empty result set is a legitimate response. This means the query will still return a mysqli_result object, and if you check its row count (either via $result->num_rows in the object-oriented style or mysqli_num_rows($result) in the procedural style) it will return 0.

mysqli_query

Для не DML-запросов (не INSERT, UPDATE или DELETE), эта функция равносильна вызову функции mysqli_real_query() , а затем mysqli_use_result() или mysqli_store_result() .

• mysqlnd на платформе Linux возвращает код ошибки 1153. Сообщение об ошибке означает размер пакета превышает max_allowed_packet байт .

• mysqlnd на платформе Windows возвращает код ошибки 2006. Это сообщение об ошибке означает отказ сервера .

• libmysqlclient на всех платформах возвращает код ошибки 2006. Это сообщение об ошибке означает отказ сервера .

Список параметров

Только для процедурного стиля: объект mysqli , полученный с помощью mysqli_connect() или mysqli_init() .

Предупреждение безопасности: SQL-инъекция

Если запрос содержит какие-либо входные переменные, вместо этого следует использовать подготавливаемые запросы. В качестве альтернативы данные должны быть правильно отформатированы и все строки должны быть экранированы с помощью функции mysqli_real_escape_string() .

Режим результата может быть одной из 3 констант, указывающих, как результат будет возвращён сервером MySQL.

MYSQLI_STORE_RESULT (по умолчанию) — возвращает объект mysqli_result с буферизованным набором результатов.

MYSQLI_USE_RESULT — возвращает объект mysqli_result с небуферизованным набором результатов. Пока есть отложенные записи, ожидающие выборки, линия соединения будет занята и все последующие вызовы будут возвращать ошибку Commands out of sync . Чтобы избежать ошибки, все записи должны быть получены с сервера или набор результатов должен быть отброшен путём вызова mysqli_free_result() .

MYSQLI_ASYNC (доступно с mysqlnd) — запрос выполняется асинхронно, набор результатов сразу не возвращается. Затем используется mysqli_poll() для получения результатов по этим запросам. Используется в сочетании с константой MYSQLI_STORE_RESULT или MYSQLI_USE_RESULT .

Возвращаемые значения

Возвращает false в случае возникновения ошибки. В случае успешного выполнения запросов, которые создают набор результатов, таких как SELECT, SHOW, DESCRIBE или EXPLAIN , mysqli_query() вернёт объект mysqli_result . Для остальных успешных запросов mysqli_query() вернёт true .

Ошибки

Если уведомления об ошибках mysqli включены ( MYSQLI_REPORT_ERROR ) и запрошенная операция не удалась, выдаётся предупреждение. Если, кроме того, установлен режим MYSQLI_REPORT_STRICT , вместо этого будет выброшено исключение mysqli_sql_exception .

Примеры

Пример #1 Пример использования mysqli::query()

mysqli_report ( MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT );
$mysqli = new mysqli ( «localhost» , «my_user» , «my_password» , «world» );

/* Создание таблицы, не возвращает набор результатов */
$mysqli -> query ( «CREATE TEMPORARY TABLE myCity LIKE City» );
printf ( «Таблица myCity создана.\n» );

/* Запросы SELECT, возвращают набор результатов */
$result = $mysqli -> query ( «SELECT Name FROM City LIMIT 10» );
printf ( «Запрос SELECT вернул %d строк.\n» , $result -> num_rows );

/* Если нужно извлечь большой объем данных, используем MYSQLI_USE_RESULT */
$result = $mysqli -> query ( «SELECT * FROM City» , MYSQLI_USE_RESULT );

/* Важно заметить, что мы не можем вызывать функции, которые взаимодействуют
с сервером, пока не закроем набор результатов. Все подобные вызовы
будут вызывать ошибку ‘out of sync’ */
$mysqli -> query ( «SET @a:=’this will not work'» );

mysqli_report ( MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT );
$link = mysqli_connect ( «localhost» , «my_user» , «my_password» , «world» );

/* Создание таблицы, не возвращает набор результатов */
mysqli_query ( $link , «CREATE TEMPORARY TABLE myCity LIKE City» );
printf ( «Таблица myCity создана.\n» );

/* Запросы SELECT, возвращают набор результатов */
$result = mysqli_query ( $link , «SELECT Name FROM City LIMIT 10» );
printf ( «Запрос SELECT вернул %d строк.\n» , mysqli_num_rows ( $result ));

/* Если нужно извлечь большой объем данных, используем MYSQLI_USE_RESULT */
$result = mysqli_query ( $link , «SELECT * FROM City» , MYSQLI_USE_RESULT );

/* Важно заметить, что мы не можем вызывать функции, которые взаимодействуют
с сервером, пока не закроем набор результатов. Все подобные вызовы
будут вызывать ошибку ‘out of sync’ */
mysqli_query ( $link , «SET @a:=’this will not work'» );

Результат выполнения данных примеров:

Смотрите также

• mysqli_real_query() — Выполнение SQL запроса
• mysqli_multi_query() — Выполняет один или несколько запросов к базе данных
• mysqli_prepare() — Подготавливает SQL выражение к выполнению
• mysqli_free_result() — Освобождает память, занятую результатами запроса

User Contributed Notes 21 notes

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.

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 ) ?> ).

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 );

Here is an example of a clean query into a html table

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.

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.

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.

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 keyword»>. $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

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.

For those using with replication enabled on their servers, add a mysqli_select_db() statement before any data modification queries. MySQL replication does not handle statements with db.table the same and will not replicate to the slaves if a scheme is not selected before.

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.

Also SET NAMES can repalce with one or some settings like SET character_set_results=’utf8′;

mysqli::query() can only execute one SQL statement.

Use mysqli::multi_query() when you want to run multiple SQL statements within one query.

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.

Hi, i created function that add a new table using array , i work with it on my projects .
<?PHP
/* this function was learned from PHP.net */
function array_keys_exist (& $key ,array & $array ) <
$keys = split ( «\|» , $key );
foreach( $keys as $key_s ) <
if( array_key_exists ( $key_s , $array )) return true ;
>
return false ;
>
/*and this is my function */
array_create_table (array & $array ) <
if( is_array ( $array )) <
$key = «table|rows|values» ;
$info = «» ;
if( array_keys_exist ( $key , $array )) <
if( is_array ( $array [ «rows» ]) and is_array ( $array [ «values» ]) )<

if( count ( $array [ «rows» ]) == count ( $array [ «values» ])) <
for( $i = 0 ; $i <= count ( $array [ «rows» ]); $i ++) <
$info = $info . » » . $array [ «rows» ][ $i ]. » » . $array [ «values» ][ $i ]. » NOT NULL » ;
if( $i < count ( $array [ «rows» ])- 1 ) $info = $info . «,» ;
>
$query = «CREATE TABLE » . $this -> private_tables_name . $array [ «table» ]. » » ;
$query .= «( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, » . $info . » )» ;
return $query ;
>
>
>else return «Error» ;
>
>

/* the use is simple */
$database = new database (); // connection to database i used mysqli .
$array = array( «table» => «MRO» , «rows» =>array( «name» , «username» ) , «values» => array( «VARCHAR (50) » , » VARCHAR (50) » ) );

$query = array_create_table ( $array ); // convert and create the query .
if( $database -> query ( $query )) echo «Work» ; else echo «Error» ; // result : work

or you could just extend the class.
in my case i already had a wraper for the db so something like this was easy :

public function free($result) <

just tried it and it works like a charm 😉

This Is A Secure Way To Use mysqli::query
———————————————————
<?php
function secured_query ( $sql )
<
$connection = new mysqli ( $host , $username , $password , $name );

if ( $connection -> connect_error )
die( «Secured» );

$result = $connection -> query ( $sql );
if( $result == FALSE )
die( «Secured» );

$connection -> close ();
return $result ;
>
/*
$host —> DataBase IP Address
$username —> DataBase Username
$password —> DataBase Password
$name —> DataBase Name
*/
?>

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