如何获取MySQL数据库中的总行数？

Question

I have many tables in my MYSQL database. I want to be able to echo the total number of all the rows in a database.

So basically I want to have it so the circled sum in the image below is echoed in PHP.

This is my current code for just displaying the total rows from one table ($txid). I have tried replaced $txid with * but it doesnt work. Any help is greatly appreciated. Thanks.

mysql_select_db($dbname);

$result = mysql_query("select count(1) FROM $txid");
$row = mysql_fetch_array($result);

$total = $row[0];
echo $total;

?>

Answer 1

Use the schema:

SELECT SUM(TABLE_ROWS) 
FROM INFORMATION_SCHEMA.TABLES 
WHERE TABLE_SCHEMA = '{DB_NAME}'

That is what phpmyadmin is using.

Source: Get record counts for all tables in MySQL database

Answer 2

There is no way to "wildcard" across multiple tables - this is one reason why normalized [row-oriented] designs are good .

Instead, the query (or queries) must be written in such a way that that all the tables are specified manually - that is, there is a separate SELECT per table. These can then be grouped with UNION ALL and SUM'ed, or summed in PHP after running each query individually.

select SUM(i) as total
from (
  select count(*) as i FROM tx
  union all
  select count(*) as i FROM tx2
  -- repeated for each table
) counts

(The SQL can be generated dynamically in PHP or in MySQL from a list of the tables to query.)

If you only need a rough estimate , then the INFORMATION_SCHEMA TABLES.TABLE_ROWS table can be queried - and indeed this presents a row-oriented design . However, at least for InnoDB tables, this is not guaranteed to return the same results as a direct COUNT.

For InnoDB tables, the row count is only a rough estimate used in SQL optimization.

Answer 3

Use the INFORMATION_SCHEMA database. It's always a nice way to obtain meta data information:

SELECT SUM(TABLE_ROWS)
    FROM INFORMATION_SCHEMA.TABLES
    WHERE TABLE_SCHEMA = 'your_database';

And here's your updated PHP code:

mysql_select_db($dbname);

$result = mysql_query("SELECT SUM(TABLE_ROWS) FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = '$dbname'");
$row = mysql_fetch_array($result);

$total = $row[0];
echo $total;

Read more about INFORMATION_SCHEMA.TABLES