如何获得 MySQL 数据库表的大小？

I can run this query to get the sizes of all tables in a MySQL database:

show table status from myDatabaseName;

I would like some help in understanding the results. I am looking for tables with the largest sizes.

Which column should I look at?

You can use this query to show the size of a table (although you need to substitute the variables first):

SELECT 
    table_name AS `Table`, 
    round(((data_length + index_length) / 1024 / 1024), 2) `Size in MB` 
FROM information_schema.TABLES 
WHERE table_schema = "$DB_NAME"
    AND table_name = "$TABLE_NAME";

or this query to list the size of every table in every database, largest first:

SELECT 
     table_schema as `Database`, 
     table_name AS `Table`, 
     round(((data_length + index_length) / 1024 / 1024), 2) `Size in MB` 
FROM information_schema.TABLES 
ORDER BY (data_length + index_length) DESC;

SELECT TABLE_NAME AS "Table Name", 
table_rows AS "Quant of Rows", ROUND( (
data_length + index_length
) /1024, 2 ) AS "Total Size Kb"
FROM information_schema.TABLES
WHERE information_schema.TABLES.table_schema = 'YOUR SCHEMA NAME/DATABASE NAME HERE'
LIMIT 0 , 30

You can get schema name from "information_schema" -> SCHEMATA table -> "SCHEMA_NAME" column

Additional You can get size of the mysql databases as following.

SELECT table_schema "DB Name", 
Round(Sum(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB" 
FROM   information_schema.tables 
GROUP  BY table_schema; 

Result

DB Name              |      DB Size in MB

mydatabase_wrdp             39.1
information_schema          0.0

You can get additional details in here.

SELECT 
    table_name AS "Table",  
    round(((data_length + index_length) / 1024 / 1024), 2) as size   
FROM information_schema.TABLES  
WHERE table_schema = "YOUR_DATABASE_NAME"  
ORDER BY size DESC; 

This sorts the sizes (DB Size in MB).

Try the following shell command (replace DB_NAME with your database name):

mysql -uroot <<<"SELECT table_name AS 'Tables', round(((data_length + index_length) / 1024 / 1024), 2) 'Size in MB' FROM information_schema.TABLES WHERE table_schema = \"DB_NAME\" ORDER BY (data_length + index_length) DESC;" | head

For Drupal/drush solution, check the following example script which will display the biggest tables in use:

#!/bin/sh
DB_NAME=$(drush status --fields=db-name --field-labels=0 | tr -d '\r\n ')
drush sqlq "SELECT table_name AS 'Tables', round(((data_length + index_length) / 1024 / 1024), 2) 'Size in MB' FROM information_schema.TABLES WHERE table_schema = \"${DB_NAME}\" ORDER BY (data_length + index_length) DESC;" | head -n20

Heres another way of working this out from using the bash command line.

for i in mysql -NB -e 'show databases'; do echo $i; mysql -e "SELECT table_name AS 'Tables', round(((data_length+index_length)/1024/1024),2) 'Size in MB' FROM information_schema.TABLES WHERE table_schema =\"$i\" ORDER BY (data_length + index_length) DESC" ; done

There is an easy way to get many informations using Workbench:

• Right-click the schema name and click "Schema inspector".

• In the resulting window you have a number of tabs. The first tab "Info" shows a rough estimate of the database size in MB.

• The second tab, "Tables", shows Data length and other details for each table.

If you are using phpmyadmin then just go to the table structure

e.g.

Space usage
Data    1.5 MiB
Index   0   B
Total   1.5 Mi

Another way of showing the number of rows and space occupied and ordering by it.

SELECT
     table_schema as `Database`,
     table_name AS `Table`,
     table_rows AS "Quant of Rows",
     round(((data_length + index_length) / 1024 / 1024/ 1024), 2) `Size in GB`
FROM information_schema.TABLES
WHERE table_schema = 'yourDatabaseName'
ORDER BY (data_length + index_length) DESC;  

The only string you have to substitute in this query is "yourDatabaseName".

If you want a query to use currently selected database. simply copy paste this query. (No modification required)

SELECT table_name ,
  round(((data_length + index_length) / 1024 / 1024), 2) as SIZE_MB
FROM information_schema.TABLES
WHERE table_schema = DATABASE() ORDER BY SIZE_MB DESC;

Adapted from ChapMic's answer to suite my particular need.

Only specify your database name, then sort all the tables in descending order - from LARGEST to SMALLEST table inside selected database. Needs only 1 variable to be replaced = your database name.

SELECT 
table_name AS `Table`, 
round(((data_length + index_length) / 1024 / 1024), 2) AS `size`
FROM information_schema.TABLES 
WHERE table_schema = "YOUR_DATABASE_NAME_HERE"
ORDER BY size DESC;

If you have ssh access, you might want to simply try du -hc /var/lib/mysql (or different datadir, as set in your my.cnf) as well.

Suppose your database name is "news_alert". Then this query will show the size of all tables in the database.

Size of all tables:

SELECT
  TABLE_NAME AS `Table`,
  ROUND(((DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024),2) AS `Size (MB)`
FROM
  information_schema.TABLES
WHERE
  TABLE_SCHEMA = "news_alert"
ORDER BY
  (DATA_LENGTH + INDEX_LENGTH)
DESC;

Output:

    +---------+-----------+
    | Table   | Size (MB) |
    +---------+-----------+
    | news    |      0.08 |
    | keyword |      0.02 |
    +---------+-----------+
    2 rows in set (0.00 sec)

For specific table:

SELECT
  TABLE_NAME AS `Table`,
  ROUND(((DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024),2) AS `Size (MB)`
FROM
  information_schema.TABLES
WHERE
    TABLE_SCHEMA = "news_alert"
  AND
    TABLE_NAME = "news"
ORDER BY
  (DATA_LENGTH + INDEX_LENGTH)
DESC;

Output:

+-------+-----------+
| Table | Size (MB) |
+-------+-----------+
| news  |      0.08 |
+-------+-----------+
1 row in set (0.00 sec)

Calculate the total size of the database at the end:

(SELECT 
  table_name AS `Table`, 
  round(((data_length + index_length) / 1024 / 1024), 2) `Size in MB` 
  FROM information_schema.TABLES 
  WHERE table_schema = "$DB_NAME"
)
UNION ALL
(SELECT 
  'TOTAL:',
  SUM(round(((data_length + index_length) / 1024 / 1024), 2) )
  FROM information_schema.TABLES 
  WHERE table_schema = "$DB_NAME"
)

SELECT table_schema, # "DB Name", 
Round(Sum(data_length + index_length) / 1024 / 1024, 1), # "DB Size in MB" 
FROM   information_schema.tables 
GROUP  BY table_schema; 

SELECT TABLE_NAME AS table_name, 
table_rows AS QuantofRows, 
ROUND((data_length + index_length) /1024, 2 ) AS total_size_kb 
FROM information_schema.TABLES
WHERE information_schema.TABLES.table_schema = 'db'
ORDER BY (data_length + index_length) DESC; 

all 2 above is tested on mysql