这应该在mysql中测试，而不是postgresql:

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; 

另一种显示所占用的行数和空间并按其排序的方法。

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;  

在这个查询中唯一需要替换的字符串是“yourDatabaseName”。

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; 

这将对大小进行排序(DB大小以MB为单位)。

我发现现有的答案实际上并没有给出磁盘上表的大小，这更有帮助。 与基于data_length的表大小相比，此查询提供了更准确的磁盘估计 和索引。我不得不在AWS RDS实例中使用这种方法，因为您无法物理地检查磁盘和检查文件大小。

select NAME as TABLENAME,FILE_SIZE/(1024*1024*1024) as ACTUAL_FILE_SIZE_GB
, round(((data_length + index_length) / 1024 / 1024/1024), 2) as REPORTED_TABLE_SIZE_GB 
from INFORMATION_SCHEMA.INNODB_SYS_TABLESPACES s
join INFORMATION_SCHEMA.TABLES t 
on NAME = Concat(table_schema,'/',table_name)
order by FILE_SIZE desc

Size of all tables: Suppose your database or TABLE_SCHEMA name is "news_alert". Then this query will show the size of all tables in the database. 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 the specific table: Suppose your TABLE_NAME is "news". Then SQL query will be- 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)

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; 

以上2个都是在mysql上测试的