mysqli::multi_query

mysqli_multi_query

(PHP 5, PHP 7, PHP 8)

mysqli::multi_query -- mysqli_multi_query — Performs one or more queries on the database

Description

Object-oriented style

public mysqli::multi_query(string $query): bool

Procedural style

mysqli_multi_query(mysqli $mysql, string $query): bool

Executes one or multiple queries which are concatenated by a semicolon.

Warning

Security warning: SQL injection

If the query contains any variable input then parameterized prepared statements should be used instead. Alternatively, the data must be properly formatted and all strings must be escaped using the mysqli_real_escape_string() function.

Queries are sent asynchronously in a single call to the database, but the database processes them sequentially. mysqli_multi_query() waits for the first query to complete before returning control to PHP. The MySQL server will then process the next query in the sequence. Once the next result is ready, MySQL will wait for the next execution of mysqli_next_result() from PHP.

It is recommended to use do-while to process multiple queries. The connection will be busy until all queries have completed and their results are fetched to PHP. No other statement can be issued on the same connection until all queries are processed. To proceed to the next query in the sequence, use mysqli_next_result(). If the next result is not ready yet, mysqli will wait for the response from the MySQL server. To check if there are more results, use mysqli_more_results().

For queries which produce a result set, such as SELECT, SHOW, DESCRIBE or EXPLAIN, mysqli_use_result() or mysqli_store_result() can be used to retrieve the result set. For queries which do not produce a result set, the same functions can be used to retrieve information such as the number of affected rows.

Tip

Executing CALL statements for stored procedures can produce multiple result sets. If the stored procedure contains SELECT statements, the result sets are returned in the order that they are produced as the procedure executes. In general, the caller cannot know how many result sets a procedure will return and must be prepared to retrieve multiple results. The final result from the procedure is a status result that includes no result set. The status indicates whether the procedure succeeded or an error occurred.

Parameters

mysql: Procedural style only: A mysqli object returned by mysqli_connect() or mysqli_init()
query: A string containing the queries to be executed. Multiple queries must be separated by a semicolon.

Return Values

Returns false if the first statement failed. To retrieve subsequent errors from other statements you have to call mysqli_next_result() first.

Errors/Exceptions

If mysqli error reporting is enabled (MYSQLI_REPORT_ERROR) and the requested operation fails, a warning is generated. If, in addition, the mode is set to MYSQLI_REPORT_STRICT, a mysqli_sql_exception is thrown instead.

Examples

Example #1 mysqli::multi_query() example

Object-oriented style

<?php

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

$query = "SELECT CURRENT_USER();";
$query .= "SELECT Name FROM City ORDER BY ID LIMIT 20, 5";

/* execute multi query */
$mysqli->multi_query($query);
do {
    /* store the result set in PHP */
    if ($result = $mysqli->store_result()) {
        while ($row = $result->fetch_row()) {
            printf("%s\n", $row[0]);
        }
    }
    /* print divider */
    if ($mysqli->more_results()) {
        printf("-----------------\n");
    }
} while ($mysqli->next_result());

Procedural style

<?php

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

$query = "SELECT CURRENT_USER();";
$query .= "SELECT Name FROM City ORDER BY ID LIMIT 20, 5";

/* execute multi query */
mysqli_multi_query($link, $query);
do {
    /* store the result set in PHP */
    if ($result = mysqli_store_result($link)) {
        while ($row = mysqli_fetch_row($result)) {
            printf("%s\n", $row[0]);
        }
    }
    /* print divider */
    if (mysqli_more_results($link)) {
        printf("-----------------\n");
    }
} while (mysqli_next_result($link));

The above examples will output something similar to:

my_user@localhost
-----------------
Amersfoort
Maastricht
Dordrecht
Leiden
Haarlemmermeer

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User Contributed Notes 22 notes

down

154

jcn50 ¶

13 years ago

WATCH OUT: if you mix $mysqli->multi_query and $mysqli->query, the latter(s) won't be executed!

<?php
// BAD CODE:
$mysqli->multi_query(" Many SQL queries ; "); // OK
$mysqli->query(" SQL statement #1 ; ") // not executed!
$mysqli->query(" SQL statement #2 ; ") // not executed!
$mysqli->query(" SQL statement #3 ; ") // not executed!
$mysqli->query(" SQL statement #4 ; ") // not executed!
?>

The only way to do this correctly is:

<?php
// WORKING CODE:
$mysqli->multi_query(" Many SQL queries ; "); // OK
while ($mysqli->next_result()) {;} // flush multi_queries
$mysqli->query(" SQL statement #1 ; ") // now executed!
$mysqli->query(" SQL statement #2 ; ") // now executed!
$mysqli->query(" SQL statement #3 ; ") // now executed!
$mysqli->query(" SQL statement #4 ; ") // now executed!
?>

down

Ivan Gabriele ¶

10 years ago

To be able to execute a $mysqli->query() after a $mysqli->multi_query() for MySQL > 5.3, I updated the code of jcn50 by this one :

<?php
    // WORKING CODE:
    $mysqli->multi_query(" Many SQL queries ; "); // OK

    while ($mysqli->next_result()) // flush multi_queries
    {
        if (!$mysqli->more_results()) break;
    }

    $mysqli->query(" SQL statement #1 ; ") // now executed!
    $mysqli->query(" SQL statement #2 ; ") // now executed!
    $mysqli->query(" SQL statement #3 ; ") // now executed!
    $mysqli->query(" SQL statement #4 ; ") // now executed!
?>

down

miqrogroove at gmail dot com ¶

11 years ago

Here are more details about error checking and return values from multi_query().  Testing shows that there are some mysqli properties to check for each result:



affected_rows

errno

error

insert_id

warning_count



If error or errno are not empty then the remaining queries did not return anything, even though error and errno will appear to be empty if processing further results is continued.



Also note that get_warnings() will not work with multi_query().  It can only be used after looping through all results, and it will only get the warnings for the last one of the queries and not for any others.  If you need to see or log query warning strings then you must not use multi_query(), because you can only see the warning_count value.

down

info at ff dot net ¶

18 years ago

Note that you need to use this function to call Stored Procedures!

If you experience "lost connection to MySQL server" errors with your Stored Procedure calls then you did not fetch the 'OK' (or 'ERR') message, which is a second result-set from a Stored Procedure call. You have to fetch that result to have no problems with subsequent queries.

Bad example, will FAIL now and then on subsequent calls:
<?php
$sQuery='CALL exampleSP('param')';
if(!mysqli_multi_query($this->sqlLink,$sQuery))
  $this->queryError();
$this->sqlResult=mysqli_store_result($this->sqlLink);
?>

Working example:
<?php
$sQuery='CALL exampleSP('param')';
if(!mysqli_multi_query($this->sqlLink,$sQuery))
  $this->queryError();
$this->sqlResult=mysqli_store_result($this->sqlLink);

if(mysqli_more_results($this->sqlLink))
  while(mysqli_next_result($this->sqlLink));
?>

Of course you can do more with the multiple results then just throwing them away, but for most this will suffice. You could for example make an "sp" function which will kill the 2nd 'ok' result.

This nasty 'OK'-message made me spend hours trying to figure out why MySQL server was logging warnings with 'bad packets from client' and PHP mysql_error() with 'Connection lost'. It's a shame the mysqli library does catch this by just doing it for you.

down

mjmendoza at grupzero dot tk ¶

17 years ago

I was developing my own CMS and I was having problem with attaching the database' sql file. I thought mysqli_multi_query got bugs where it crashes my MySQL server. I tried to report the bug but it showed that it has duplicate bug reports of other developers. To my surprise, mysqli_multi_query needs to bother with result even if there's none.

I finally got it working when I copied the sample and removed somethings. Here is what it looked liked

<?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();
}

$query  = "CREATE TABLE....;...;... blah blah blah;...";

/* execute multi query */
if (mysqli_multi_query($link, $query)) {
   do {
       /* store first result set */
       if ($result = mysqli_store_result($link)) {
           //do nothing since there's nothing to handle
           mysqli_free_result($result);
       }
       /* print divider */
       if (mysqli_more_results($link)) {
           //I just kept this since it seems useful
           //try removing and see for yourself
       }
   } while (mysqli_next_result($link));
}

/* close connection */
mysqli_close($link);
?>

bottom-line: I think mysql_multi_query should only be used for attaching a database. it's hard to handle results from 'SELECT' statements inside a single while loop.

down

vicky dot gonsalves at outlook dot com ¶

10 years ago

Following code can be used to resolve 
mysqli::next_result(): There is no next result set. Please, call mysqli_more_results()/mysqli::more_results() to check whether to call this function/method 

        $query = "SELECT SOME_COLUMN FROM SOME_TABLE_NAME;";
        $query .= "SELECT SOME_OTHER_COLUMN FROM SOME_TABLE_NAME";
        /* execute multi query */
        if (mysqli_multi_query($this->conn, $query)) {
            $i = true;
            do {
                /* store first result set */
                if ($result = mysqli_store_result($this->conn)) {
                    while ($row = mysqli_fetch_row($result)) {
                        printf("%s\n", $row[0]);
                    }
                    mysqli_free_result($result);
                }
                /* print divider */
                if (mysqli_more_results($this->conn)) {
                    $i = true;
                    printf("-----------------\n");
                } else {
                    $i = false;
                }
            } while ($i && mysqli_next_result($this->conn));
        }

down

Miles ¶

15 years ago

You can use prepared statements on stored procedures.

You just need to flush all the subsequent result sets before closing the statement... so:

$mysqli_stmt = $mysqli->prepare(....);

... bind, execute, bind, fetch ...

while($mysqli->more_results())
{
    $mysqli->next_result();
    $discard = $mysqli->store_result();
}

$mysqli_stmt->close();

Hope that helps :o)

down

Lubaev K ¶

11 years ago

Use generator. 
PHP 5.5.0
<?php
// Quick multiQuery func.
function multiQuery( mysqli $mysqli, $query ) {
    if ($mysqli->multi_query( $query )) {
    do {
        if ($result = $mysqli->store_result()) {
            while ($row = $result->fetch_row()) {
                foreach ($row as $key => $value) yield $key => $value;
            }
            $result->free();
        }
    } while( $mysqli->more_results() && $mysqli->next_result() );
    }
}

$query = "OPTIMIZE TABLE `question`;" .
         "LOCK TABLES `question` READ;" . 
         "SELECT * FROM `question` WHERE `questionid`=2;" . 
         "SELECT * FROM `question` WHERE `questionid`=7;" . 
         "SELECT * FROM `question` WHERE `questionid`=8;" . 
         "SELECT * FROM `question` WHERE `questionid`=9;" . 
         "SELECT * FROM `question` WHERE `questionid`=11;" . 
         "SELECT * FROM `question` WHERE `questionid`=12;" . 
         "UNLOCK TABLES;" . 
         "TRUNCATE TABLE `question`;";

$mysqli = new mysqli('localhost', 'user', 'pswd', 'dbnm');
$mysqli->set_charset("cp1251");

// result
foreach ( multiQuery($mysqli, $query) as $key => $value ) {
    echo $key, $value, PHP_EOL;
}

?>
Good luck!

down

skunkbad ¶

10 years ago

I appreciate the advice from crmccar at gmail dot com regarding the proper way to check for errors, but I would get an error with his/her code. I fixed it by changing the code a little:

<?php
$sql = file_get_contents( 'sql/test_' . $id . '_data.sql');

$query_array = explode(';', $sql);

// Run the SQL
$i = 0;
if( $this->mysqli->multi_query( $sql ) )
{
    do {
        $this->mysqli->next_result();

        $i++;
    }
    while( $this->mysqli->more_results() ); 
}

if( $this->mysqli->errno )
{
    die(
        '<h1>ERROR</h1>
        Query #' . ( $i + 1 ) . ' of <b>test_' . $id . '_data.sql</b>:<br /><br />
        <pre>' . $query_array[ $i ] . '</pre><br /><br /> 
        <span style="color:red;">' . $this->mysqli->error . '</span>'
    );
}
?>

down

crmccar at gmail dot com ¶

13 years ago

I'd like to reinforce the correct way of catching errors from the queries executed by multi_query(), since the manual's examples don't show it and it's easy to lose UPDATEs, INSERTs, etc. without knowing it.



$mysqli->next_result() will return false if it runs out of statements OR if the next statement has an error. Therefore, it's important to check for errors when the loop ends. Also, I believe it's useful to know when and where the loop broke, so consider the following code:



<?php

$statements = array("INSERT INTO tablename VALUES ('1', 'one')", "INSERT INTO tablename VALUES ('2', 'two')");

if ($mysqli->multi_query(implode(';', $statements))) {

    $i = 0;

    do {

        $i++;

    } while ($mysqli->next_result());

}

if ($mysqli->errno) {

    echo "Batch execution prematurely ended on statement $i.\n";

    var_dump($statements[$i], $mysqli->error);

}

?>



The IF statement on the multi_query() call checks the first result, because next_result() starts at the second.

down

keksov at gmail dot com ¶

11 years ago

If you want to create a table with triggers, procedures or functions in one multiline query you may stuck with a error -
#1064 - You have an error in your SQL syntax; xxx corresponds to your MySQL server version for the right syntax to use near 'DELIMITER' at line 1

The solution is very simple - don't use DELIMITER keyword at all! So, instead of :

DELIMITER |
CREATE TRIGGER $dbName.$iname BEFORE INSERT ON $table FOR EACH ROW
BEGIN
    <body>
EOT|
DELIMITER ;

just use :

CREATE TRIGGER $dbName.$iname BEFORE INSERT ON $table FOR EACH ROW
BEGIN
    <body>
EOT;

For more information read answers at StackOverflow for question #5311141 

http://stackoverflow.com/questions/5311141/how-to-execute-mysql-command-delimiter

down

Anonymous ¶

13 years ago

If your second or late query returns no result or even if your query is not a valid SQL query, more_results(); returns true in any case.

down

Shawn Pyle ¶

14 years ago

Be sure to not send a set of queries that are larger than max_allowed_packet size on your MySQL server. If you do, you'll get an error like: 
Mysql Error (1153): Got a packet bigger than 'max_allowed_packet' bytes

To see your MySQL size limitation, run the following query: show variables like 'max_allowed_packet';

or see http://dev.mysql.com/doc/refman/5.1/en/packet-too-large.html

down

jlong at carouselchecks dot com ¶

12 years ago

Getting "Error: Commands out of sync; you can't run this command now" after running a multi-query? Make sure you've cleared out the queue of results.

Here's what I've used to discard all subsequent results from a multi-query:

<?php
while($dbLink->more_results() && $dbLink->next_result()) {
    $extraResult = $dbLink->use_result();
    if($extraResult instanceof mysqli_result){
        $extraResult->free();
    }
}

?>

down

-1

ashteroid ¶

4 years ago

To get the affected/selected row count from all queries

$q = "UPDATE `Review` SET `order` = 1 WHERE id = 600;" // aff 1
       .  "UPDATE `Review` SET `order` = 600 WHERE id = 1;" //aff 1
    . "SELECT 0;" //for testing, aff rows == -1
                    ;
    
    $affcnt = 0;
    $rowcnt = 0;
        
    $res = $db->multi_query($q);
    if($res == false)
        Lib::throw( $q . "\n[" . $db->errno . "]\n" . $db->error . "\n" );    
    do
    {
        $affcnt += $db->affected_rows;
        if( isset($res->num_rows) )
            $rowcnt += $res->num_rows;
    }
    while( $db->more_results() && $res = $db->next_result() );
    //IMPORTANT: call more_results First!, THEN next_result to get new data.
        
    return $res;

down

Stjepan Brbot ¶

8 years ago

This example shows how to read data from multiple stored procedures. Here I have two stored procedures proc1() and proc2() and retrieve their data into 2D array:

<?php

$db=new mysqli(...);

$sql="CALL proc1(...); CALL proc2(...);";

$procs=[]; //outer array for resultsets (tables)
$cols=[]; //inner array for columns (fields)

if($db->multi_query($sql))
{
  do
  {
    $db->next_result();
    if($rst=$db->use_result())
    {
      while($row=$rst->fetch_row())
      {
          $cols[]=$row[0]; //fetch 1st column value
          $cols[]=$row[1]; //fetch 2nd column value
      }
      $procs[]=$cols; //add cols to procedures array
    }
  }
  while($this->db->more_results());
}

?>

down

luka8088 at owave dot net ¶

14 years ago

if you don't iterate through all results you get "server has gone away" error message ...

to resolve this, in php 5.2 it is enough to use

<?php
  // ok for php 5.2
  while ($mysqli->next_result());
?>

to drop unwanted results, but in php 5.3 using only this throws

mysqli::next_result(): There is no next result set. Please, call mysqli_more_results()/mysqli::more_results() to check whether to call this function/method

so it should be replaced with

<?php
  // ok for php 5.3
  while ($mysqli->more_results() && $mysqli->next_result());
?>

I also tried but failed:

<?php

  // can create infinite look in some cases
  while ($mysqli->more_results())
    $mysqli->next_result();

  // also throws error in some cases
  if ($mysqli->more_results())
    while ($mysqli->next_result());

?>

down

jparedes at gmail dot com ¶

16 years ago

It's very important that after executing mysqli_multi_query you have first process the resultsets before sending any another statement to the server, otherwise your
socket is still blocked.

Please note that even if your multi statement doesn't contain SELECT queries, the server will send result packages containing errorcodes (or OK packet) for single statements.

down

-1

undefined(AT)users(DOT)berlios(DOT)de ¶

16 years ago

mysqli_multi_query handles MySQL Transaction on InnoDB's :-)



<?php



$mysqli  = mysqli_connect( "localhost", "owner", "pass", "db", 3306, "/var/lib/mysql/mysql.sock" );



$QUERY = <<<EOT

START TRANSACTION;

SELECT @lng:=IF( STRCMP(`main_lang`,'de'), 'en', 'de' )

FROM `main_data` WHERE  ( `main_activ` LIKE 1 ) ORDER BY `main_id` ASC;

SELECT `main_id`, `main_type`, `main_title`, `main_body`, `main_modified`, `main_posted`

FROM `main_data`

WHERE ( `main_type` RLIKE "news|about" AND `main_lang` LIKE @lng AND `main_activ` LIKE 1 )

ORDER BY `main_type` ASC;

COMMIT;

EOT;



$query = mysqli_multi_query( $mysqli, $QUERY ) or die( mysqli_error( $mysqli ) );



if( $query )

{

  do {

    if( $result = mysqli_store_result( $mysqli ) )

    {

      $subresult = mysqli_fetch_assoc( $result );

      if( ! isset( $subresult['main_id'] ) )

        continue;



      foreach( $subresult AS $k => $v )

      {

        var_dump( $k , $v );

      }

    }

  } while ( mysqli_next_result( $mysqli ) );

}



mysqli_close( $mysqli );



?>

down

-1

ASchmidt at Anamera dot net ¶

6 years ago

Multi-queries open the potential for a SQL injection. 

The often cited "fallback" loop:

<?php
while ( $db->more_results() and $db->next_result() ) {
  $rs = $db->use_result();
  if( $rs instanceof \mysqli_result ) {
      $rs->free();
}
?>

certainly will avoid the dreaded error 2014 "Commands out of sync; you can't run this command now" error. However, that technique will completely disregard the fact that any excess result sets are a likely indication of an infiltrated system.

Instead, it may be wise to tightly manage the correct number of expected, individual result sets and throw an exception of more are received.

However, it's important to understand that any closing comment (which might have been appended as one defense against command appending) will result in an EXTRA, EMPTY result set.

Example:

SELECT SQL_CALC_FOUND_ROWS * FROM `table` LIMIT 10; SELECT FOUND_ROWS(); --

will produce THREE result sets:

#1 - the ten data rows,
#2 - the overall row count,
#3 - an empty result set, where: FALSE === $db->use_result(), even though it had been TRUE === ($db->more_results() and $db->next_result() ) .

down

-5

levani0101 at yahoo dot com ¶

10 years ago

Please note that there is no need for the semicolon after the last query. That wasted more than hour of my time...

down

-4

jesper at hermandsen dot dk ¶

9 years ago

If you're importing a sql-file with triggers, functions, stored procedures and other stuff, you'll might be using DELIMITER in MySQL.
Notice: This function assumes that all delimiters are on it's own line, and that "DELIMITER" are in all caps.

<?php
function mysqli_multi_query_file($mysqli, $filename) {
    $sql = file_get_contents($filename);
    // remove comments
    $sql = preg_replace('#/\*.*?\*/#s', '', $sql);
    $sql = preg_replace('/^-- .*[\r\n]*/m', '', $sql);
    if (preg_match_all('/^DELIMITER\s+(\S+)$/m', $sql, $matches, PREG_SET_ORDER | PREG_OFFSET_CAPTURE)) {
        $prev = null;
        $index = 0;
        foreach ($matches as $match) {
            $sqlPart = substr($sql, $index, $match[0][1] - $index);
            // move cursor after the delimiter
            $index = $match[0][1] + strlen($match[0][0]);
            if ($prev && $prev[1][0] != ';') {
                $sqlPart = explode($prev[1][0], $sqlPart);
                foreach ($sqlPart as $part) {
                    if (trim($part)) { // no empty queries
                        $mysqli->query($part);
                    }
                }
            } else {
                if (trim($sqlPart)) { // no empty queries
                    $mysqli->multi_query($sqlPart);
                    while ($mysqli->next_result()) {;}
                }
            }
            $prev = $match;
        }
        // run the sql after the last delimiter
        $sqlPart = substr($sql, $index, strlen($sql)-$index);
        if ($prev && $prev[1][0] != ';') {
            $sqlPart = explode($prev[1][0], $sqlPart);
            foreach ($sqlPart as $part) {
                if (trim($part)) {
                    $mysqli->query($part);
                }
            }
        } else {
            if (trim($sqlPart)) {
                $mysqli->multi_query($sqlPart);
                while ($mysqli->next_result()) {;}
            }
        }
    } else {
        $mysqli->multi_query($sql);
        while ($mysqli->next_result()) {;}
    }
}
?>

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mysqli::multi_query

mysqli_multi_query

Description

Security warning: SQL injection

Parameters

Return Values

Errors/Exceptions

Examples

See Also

Improve This Page

User Contributed Notes 22 notes