SQL Server 2008: How to query all databases sizes?

Question

with fs
as
(
    select database_id, type, size * 8.0 / 1024 size
    from sys.master_files
)
select 
    name,
    (select sum(size) from fs where type = 0 and fs.database_id = db.database_id) DataFileSizeMB,
    (select sum(size) from fs where type = 1 and fs.database_id = db.database_id) LogFileSizeMB
from sys.databases db

I don't know exactly what you mean by efficiency but this is straightforward and it works for me:

SELECT
    DB_NAME(db.database_id) DatabaseName,
    (CAST(mfrows.RowSize AS FLOAT)*8)/1024 RowSizeMB,
    (CAST(mflog.LogSize AS FLOAT)*8)/1024 LogSizeMB,
    (CAST(mfstream.StreamSize AS FLOAT)*8)/1024 StreamSizeMB,
    (CAST(mftext.TextIndexSize AS FLOAT)*8)/1024 TextIndexSizeMB
FROM sys.databases db
    LEFT JOIN (SELECT database_id, SUM(size) RowSize FROM sys.master_files WHERE type = 0 GROUP BY database_id, type) mfrows ON mfrows.database_id = db.database_id
    LEFT JOIN (SELECT database_id, SUM(size) LogSize FROM sys.master_files WHERE type = 1 GROUP BY database_id, type) mflog ON mflog.database_id = db.database_id
    LEFT JOIN (SELECT database_id, SUM(size) StreamSize FROM sys.master_files WHERE type = 2 GROUP BY database_id, type) mfstream ON mfstream.database_id = db.database_id
    LEFT JOIN (SELECT database_id, SUM(size) TextIndexSize FROM sys.master_files WHERE type = 4 GROUP BY database_id, type) mftext ON mftext.database_id = db.database_id

With results like:

DatabaseName  RowSizeMB LogSizeMB StreamSizeMB TextIndexSizeMB
------------- --------- --------- ------------ ---------------
master        4         1.25      NULL         NULL
model         2.25      0.75      NULL         NULL
msdb          14.75     8.1875    NULL         NULL
tempdb        8         0.5       NULL         NULL

Note: was inspired by this article

Here's a simple, quick and reliable query that will give all database and log file names, sizes and also database statuses (e.g. ONLINE) in a nice, easy to read output:

SELECT
    D.name,
    F.Name AS FileType,
    F.physical_name AS PhysicalFile,
    F.state_desc AS OnlineStatus,
    CAST(F.size AS bigint) * 8*1024 AS SizeInBytes,
    CAST((F.size*8.0)/1024/1024 AS decimal(18,3)) AS SizeInGB
FROM 
    sys.master_files F
    INNER JOIN sys.databases D ON D.database_id = F.database_id
ORDER BY SizeInBytes desc

with Total Database size ordered Desc

SELECT     
DB_NAME(db.database_id) DatabaseName,     
(CAST(mfrows.RowSize AS FLOAT)*8)/1024 RowSizeMB,     
(CAST(mflog.LogSize AS FLOAT)*8)/1024 LogSizeMB, 
(CAST(mfrows.RowSize AS FLOAT)*8)/1024/1024+(CAST(mflog.LogSize AS FLOAT)*8)/1024/1024 DBSizeG,
(CAST(mfstream.StreamSize AS FLOAT)*8)/1024 StreamSizeMB,     
(CAST(mftext.TextIndexSize AS FLOAT)*8)/1024 TextIndexSizeMB 
FROM sys.databases db     
LEFT JOIN (SELECT database_id, 
                  SUM(size) RowSize 
            FROM sys.master_files 
            WHERE type = 0 
            GROUP BY database_id, type) mfrows 
    ON mfrows.database_id = db.database_id     
LEFT JOIN (SELECT database_id, 
                  SUM(size) LogSize 
            FROM sys.master_files 
            WHERE type = 1 
            GROUP BY database_id, type) mflog 
    ON mflog.database_id = db.database_id     
LEFT JOIN (SELECT database_id, 
                  SUM(size) StreamSize 
                  FROM sys.master_files 
                  WHERE type = 2 
                  GROUP BY database_id, type) mfstream 
    ON mfstream.database_id = db.database_id     
LEFT JOIN (SELECT database_id, 
                  SUM(size) TextIndexSize 
                  FROM sys.master_files 
                  WHERE type = 4 
                  GROUP BY database_id, type) mftext 
    ON mftext.database_id = db.database_id 
       ORDER BY 4 DESC

All seem overly complicated! Or am I missing something?

Surely all you need is something like:

select d.name, case when m.type = 0 then 'Data' else 'Log' end,  m.size * 8 / 1024
from sys.master_files m JOIN sys.databases d ON d.database_id = m.database_id

or if you don't want the log:

select d.name, m.size * 8 / 1024
from sys.master_files m JOIN sys.databases d ON d.database_id = m.database_id and m.type =0

SELECT
    DB.name,
    SUM(CASE WHEN type = 0 THEN MF.size * 8 / 1024 ELSE 0 END) AS DataFileSizeMB,
    SUM(CASE WHEN type = 1 THEN MF.size * 8 / 1024 ELSE 0 END) AS LogFileSizeMB
FROM
    sys.master_files MF
    JOIN sys.databases DB ON DB.database_id = MF.database_id
GROUP BY DB.name
ORDER BY DataFileSizeMB DESC

please find more deatils or download the script from below link https://gallery.technet.microsoft.com/SIZE-OF-ALL-DATABASES-IN-0337f6d5#content

 DECLARE @spacetable table
 (
 database_name varchar(50) ,
 total_size_data int,
 space_util_data int,
 space_data_left int,
 percent_fill_data float,
 total_size_data_log int,
 space_util_log int,
 space_log_left int,
 percent_fill_log char(50),
 [total db size] int,
 [total size used] int,
 [total size left] int
 )
 insert into  @spacetable
 EXECUTE master.sys.sp_MSforeachdb 'USE [?];
 select x.[DATABASE NAME],x.[total size data],x.[space util],x.[total size data]-x.[space util] [space left data],
 x.[percent fill],y.[total size log],y.[space util],
 y.[total size log]-y.[space util] [space left log],y.[percent fill],
 y.[total size log]+x.[total size data] ''total db size''
 ,x.[space util]+y.[space util] ''total size used'',
 (y.[total size log]+x.[total size data])-(y.[space util]+x.[space util]) ''total size left''
  from (select DB_NAME() ''DATABASE NAME'',
 sum(size*8/1024) ''total size data'',sum(FILEPROPERTY(name,''SpaceUsed'')*8/1024) ''space util''
 ,case when sum(size*8/1024)=0 then ''less than 1% used'' else
 substring(cast((sum(FILEPROPERTY(name,''SpaceUsed''))*1.0*100/sum(size)) as CHAR(50)),1,6) end ''percent fill''
 from sys.master_files where database_id=DB_ID(DB_NAME())  and  type=0
 group by type_desc  ) as x ,
 (select 
 sum(size*8/1024) ''total size log'',sum(FILEPROPERTY(name,''SpaceUsed'')*8/1024) ''space util''
 ,case when sum(size*8/1024)=0 then ''less than 1% used'' else
 substring(cast((sum(FILEPROPERTY(name,''SpaceUsed''))*1.0*100/sum(size)) as CHAR(50)),1,6) end ''percent fill''
 from sys.master_files where database_id=DB_ID(DB_NAME())  and  type=1
 group by type_desc  )y'
 select * from @spacetable
 order by database_name