如何获得 mysql 数据库的大小？

How to get size of a mysql database?
Suppose the target database is called "v3".

Run this query and you'll probably get what you're looking for:

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; 

This query comes from the mysql forums, where there are more comprehensive instructions available.

Alternatively you can directly jump into data directory and check for combined size of v3.myd, v3. myi and v3. frm files (for myisam) or v3.idb & v3.frm (for innodb).

Alternatively, if you are using phpMyAdmin, you can take a look at the sum of the table sizes in the footer of your database structure tab. The actual database size may be slightly over this size, however it appears to be consistent with the table_schema method mentioned above.

Screen-shot :

To get a result in MB:

SELECT  SUM(ROUND(((DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024 ), 2)) AS "SIZE IN MB"
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = "SCHEMA-NAME";`

To get a result in GB:

SELECT  SUM(ROUND(((DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024 /1024 ), 2))  AS "SIZE IN GB"
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = "SCHEMA-NAME";`

mysqldiskusage  --server=root:MyPassword@localhost  pics

+----------+----------------+
| db_name  |         total  |
+----------+----------------+
| pics     | 1,179,131,029  |
+----------+----------------+

It can be determined by using following MySQL command

SELECT table_schema AS "Database", SUM(data_length + index_length) / 1024 / 1024 AS "Size (MB)" FROM information_schema.TABLES GROUP BY table_schema

Result

Database    Size (MB)
db1         11.75678253
db2         9.53125000
test        50.78547382

Get result in GB

SELECT table_schema AS "Database", SUM(data_length + index_length) / 1024 / 1024 / 1024 AS "Size (GB)" FROM information_schema.TABLES GROUP BY table_schema

Go into the mysql data directory and run du -h --max-depth=1 | grep databasename