mysql_list_tables

(PHP 4, PHP 5)

mysql_list_tables — 列出 MySQL 数据库中的表

说明

resource mysql_list_tables ( string $database [, resource $link_identifier ] )

mysql_list_tables() 接受一个数据库名并返回和 mysql_query() 函数很相似的一个结果指针。用 mysql_tablename() 函数来遍历此结果指针，或者任何使用结果表的函数，例如 mysql_fetch_array() 。

database 参数是需要被取得其中的的表名的数据库名。如果失败 mysql_list_tables() 返回 FALSE 。

为向下兼容仍然可以使用本函数的别名 mysql_listtables() ，但反对这样做。

Note: 该函数已经被删除了，请不要再使用该函数。您可以用命令 SHOW TABLES FROM DATABASE 来实现该函数的功能。

Example #1 mysql_list_tables() 例子

  <?php
    $dbname  =  'mysql_dbname' ;

    if (! mysql_connect ( 'mysql_host' ,  'mysql_user' ,  'mysql_password' )) {
        print  'Could not connect to mysql' ;
        exit;
    }

     $result  =  mysql_list_tables ( $dbname );

    if (! $result ) {
        print  "DB Error, could not list tables\n" ;
        print  'MySQL Error: '  .  mysql_error ();
        exit;
    }

    while ( $row  =  mysql_fetch_row ( $result )) {
        print  "Table:  $row [ 0 ] \n" ;
    }

     mysql_free_result ( $result );
 ?>

参见 mysql_list_dbs() 和 mysql_tablename() 。

用户评论:

[#1] bimal at sanjaal dot com [2013-02-28 09:22:21]

A better alternative to mysql_list_tables() would be the following mysql_tables() function.

<?php function mysql_tables($database='') { $tables = array(); $list_tables_sql = "SHOW TABLES FROM {$database};"; $result = mysql_query($list_tables_sql); if($result) while($table = mysql_fetch_row($result)) { $tables[] = $table[0]; } return $tables; } # Usage example $tables = mysql_tables($database_local); ?>

[#2] kroczu at interia dot pl [2006-12-08 03:01:52]

<?php // here is a much more elegant method to check if a table exists ( no error generate) if( mysql_num_rows( mysql_query("SHOW TABLES LIKE '".$table."'"))) { //... } ?>

[#3] mrkvomail at centrum dot cz [2006-01-29 11:48:21]

You can also do this with function mysql_query(). It's better because mysql_list_tables is old function and you can stop showing errors.

function mysql_table_exists($dbLink, $database, $tableName)
{
   $tables = array();
   $tablesResult = mysql_query("SHOW TABLES FROM $database;", $dbLink);
   while ($row = mysql_fetch_row($tablesResult)) $tables[] = $row[0];
    if (!$result) {
    }
   return(in_array($tableName, $tables));
}

[#4] Anonymous [2005-12-15 06:38:42]

Getting the database status:
<?php // Get database status by DtTvB // Connect first mysql_connect ('*********', '*********', '********'); mysql_select_db ('*********'); // Get the list of tables $sql = 'SHOW TABLES FROM *********'; if (!$result = mysql_query($sql)) { die ('Error getting table list (' . $sql . ' :: ' . mysql_error() . ')'); } // Make the list of tables an array $tablerow = array(); while ($row = mysql_fetch_array($result)) { $tablerow[] = $row; } // Define variables... $total_tables = count($tablerow); $statrow = array(); $total_rows = 0; $total_rows_average = 0; $sizeo = 0; // Get the status of each table for ($i = 0; $i < count($tablerow); $i++) { // Query the status... $sql = "SHOW TABLE STATUS LIKE '{$tablerow[$i][0]}';"; if (!$result = mysql_query($sql)) { die ('Error getting table status (' . $sql . ' :: ' . mysql_error() . ')'); } // Get the status array of this table $table_info = mysql_fetch_array($result); // Add them to the total results $total_rows += $table_info[3]; $total_rows_average += $table_info[4]; $sizeo += $table_info[5]; } // Function to calculate size of the file function c2s($bs) { if ($bs < 964) { return round($bs) . " Bytes"; } else if ($bs < 1000000) { return round($bs/1024,2) . " KB" ; } else { return round($bs/1048576,2) . " MB" ; } } // Echo the result!!!!!!!!! echo "{$total_rows} rows in {$total_tables} tables"; echo " Average size in each row: " . c2s($total_rows_average/$total_tables); echo " Average size in each table: " . c2s($sizeo/$total_tables); echo " Database size: " . c2s($sizeo); // Close the connection mysql_close(); ?>

[#5] daveheslop (dave heslop) [2005-05-07 16:45:32]

Worth noting for beginners: using a row count to test for the existence of a table only works if the table actually contains data, otherwise the test will return false even if the table exists.

[#6] wbphfox at xs4all dot nl [2003-09-09 09:55:04]

Here is a way to show al the tables and have the function to drop them...

<?php echo ""; //this is the connection file for the database.... $connectfile = "connect.php"; require $connectfile; $dbname = 'DATABASE NAME'; $result = mysql_list_tables($dbname); echo "<table width=\"75%\" border=\"0\">"; echo "<tr bgcolor=\"#993333\"> "; echo "<td>Table name:</td>"; echo "<td>Delete?</td>"; echo "</tr>"; if (!$result) { print "DB Error, could not list tables\n"; print 'MySQL Error: ' . mysql_error(); exit; } while ($row = mysql_fetch_row($result)) { echo "<tr bgcolor=\"#CCCCCC\">"; echo "<td>"; print "$row[0]\n"; echo "</td>"; echo "<td>"; echo "<a href=\"$PHP_SELF?action=delete&table="; print "$row[0]\n"; echo "\">Yes?</a>"; echo "</td>"; echo "</tr>"; } mysql_free_result($result); //Delete if($action=="delete") { $deleteIt=mysql_query("DROP TABLE $table"); if($deleteIt) { echo "The table \""; echo "$table\" has been deleted with succes! "; } else { echo "An error has occured...please try again "; } } ?>

[#7] thebitman at attbi dot com [2003-05-07 01:49:37]

okay everybody, the fastest, most accurate, safest method:

function mysql_table_exists($table, $link)
{
     $exists = mysql_query("SELECT 1 FROM `$table` LIMIT 0", $link);
      if ($exists) return true;
     return false;
}

Note the "LIMIT 0", I mean come on, people, can't get much faster than that! :)
As far as a query goes, this does absolutely nothing. But it has the ability to fail if the table doesnt exist, and that's all you need!

[#8] daevid at daevid dot com [2002-12-17 04:36:55]

I was in need of a way to create a database, complete with tables from a .sql file. Well, since PHP/mySQL doesn't allow that it seems, the next best idea was to create an empty template database and 'clone & rename it'. Guess what? There is no mysql_clone_db() function or any SQL 'CREATE DATABASE USING TEMPLATEDB' command. grrr...

So, this is the hack solution I came up with:

$V2DB = "V2_SL".$CompanyID;

$result = mysql_create_db($V2DB, $linkI);
if (!$result) $errorstring .= "Error creating ".$V2DB." database \n".mysql_errno($linkI).": ".mysql_error($linkI)." \n";

mysql_select_db ($V2DB, $linkI) or die ("Could not select ".$V2DB." Database");

//You must have already created the "V2_Template" database.
//This will make a clone of it, including data.

$tableResult = mysql_list_tables ("V2_Template");
while ($row = mysql_fetch_row($tableResult))
{
$tsql = "CREATE TABLE ".$V2DB.".".$row[0]." AS SELECT * FROM V2_Template.".$row[0];
echo $tsql." \n";
$tresult = mysql_query($tsql,$linkI);
if (!$tresult) $errorstring .= "Error creating ".$V2DB.".".$row[0]." table \n".mysql_errno($linkI).": ".mysql_error($linkI)." \n";
}

[#9] cdarklock at darklock dot com [2002-12-06 08:03:03]

Actually, the initially posted SELECT COUNT(*) approach is flawless. SELECT COUNT(*) will provide one and only one row in response unless you can't select from the table at all. Even a brand new (empty) table responds with one row to tell you there are 0 records.

While other approaches here are certainly functional, the major problem comes up when you want to do something like check a database to ensure that all the tables you need exist, as I needed to do earlier today. I wrote a function called tables_needed() that would take an array of table names -- $check -- and return either an array of tables that did not exist, or FALSE if they were all there. With mysql_list_tables(), I came up with this in the central block of code (after validating parameters, opening a connection, selecting a database, and doing what most people would call far too much error checking):

if($result=mysql_list_tables($dbase,$conn))
{ // $count is the number of tables in the database
 $count=mysql_num_rows($result);
 for($x=0;$x<$count;$x++)
 {
 $tables[$x]=mysql_tablename($result,$x);
 }
 mysql_free_result($result);
 // LOTS more comparisons here
 $exist=array_intersect($tables,$check);
 $notexist=array_diff($exist,$check);
 if(count($notexist)==0)
 {
 $notexist=FALSE;
 }
}

The problem with this approach is that performance degrades with the number of tables in the database. Using the "SELECT COUNT(*)" approach, performance only degrades with the number of tables you *care* about:

// $count is the number of tables you *need*
$count=count($check);
for($x=0;$x<$count;$x++)
{
 if(mysql_query("SELECT COUNT(*) FROM ".$check[$x],$conn)==FALSE)
 {
 $notexist[count($notexist)]=$check[$x];
 }
}
if(count($notexist)==0)
{
 $notexist=FALSE;
}

While the increase in speed here means virtually nothing to the average user who has a database-driven backend on his personal web site to handle a guestbook and forum that might get a couple hundred hits a week, it means EVERYTHING to the professional who has to handle tens of millions of hits a day... where a single extra millisecond on the query turns into more than a full day of processing time. Developing good habits when they don't matter keeps you from having bad habits when they *do* matter.

[#10] [2002-10-29 17:42:01]

<?php function getdbsize($tdb) { $db_host='localhost'; $db_usr='USER'; $db_pwd='XXXXXXXX'; $db = mysql_connect($db_host, $db_usr, $db_pwd) or die ("Error connecting to MySQL Server!\n"); mysql_select_db($tdb, $db); $sql_result = "SHOW TABLE STATUS FROM " .$tdb; $result = mysql_query($sql_result); mysql_close($db); if($result) { $size = 0; while ($data = mysql_fetch_array($result)) { $size = $size + $data["Data_length"] + $data["Index_length"]; } return $size; } else { return FALSE; } } ?>

<?php $tmp = getdbsize("DATABASE_NAME"); if (!$tmp) { echo "ERROR!"; } else { echo $tmp; } ?>

[#11] mail at thomas-hoerner dot de [2002-10-04 09:24:12]

You can also use mysql_fetch_object if you consider a specialty: The name of the object-var is

Tables_in_xxxxx

where xxxxx is the name of the database.

i.e. use

$result = mysql_list_tables($dbname);
$varname="Tables_in_".$dbname;
while ($row = mysql_fetch_object($result)) {
echo $row->$varname;
};

[#12] NewToPHP_Guy at Victoria dot NOSPAM dot com [2002-10-02 14:06:35]

The example by PHP-Guy to determine if a table exists is interesting and useful (thanx), except for one tiny detail. The function 'mysql_list_tables()' returns table names in lower case even when tables are created with mixed case. To get around this problem, add the 'strtolower()' function in the last line as follows:

return(in_array(strtolower($tableName), $tables));

[#13] coffee at hayekheaven dot net [2002-06-17 17:48:37]

Even though php guy's solution is probably the fastest here's another one just for the heck of it...
I use this function to check whether a table exists. If not it's created.

mysql_connect("server","usr","pwd")
or die("Couldn't connect!");
mysql_select_db("mydb");

$tbl_exists = mysql_query("DESCRIBE sometable");
if (!$tbl_exists) {
mysql_query("CREATE TABLE sometable (id int(4) not null primary key,
somevalue varchar(50) not null)");
}