MySQL Convert Bytes to Kilobytes, Megabytes, Gigabytes - mysql

Question

I have a logs table that stores various file sizes in bytes. I want to be able to query the database and return the smallest possible float which has been converted to MB GB etc. At present I can return the value in MB but how do I continue to divide further to smallest value and append the unit?
SELECT CONCAT( ROUND( SUM( data_transferred ) /1048576, 2 ) , ' MB' )
FROM `logs`
Any help would be appreciated.
UPDATE:
Based on the link voodoo417 provided I updated my query to the following, which will output the most relevant file size to two decimal places and append the unit (1000 Bytes, 1 KB, 500 MB, 2 GB, etc):
SET #bytes := (SELECT SUM(data_transferred) FROM wp_ddownload_statistics);
SELECT
CASE
WHEN ABS(#bytes) < 1024 THEN CONCAT( ROUND( #bytes, 2 ), ' Bytes')
WHEN ABS(#bytes) < 1048576 THEN CONCAT( ROUND( (#bytes/1024), 2 ), ' KB')
WHEN ABS(#bytes) < 1073741824 THEN CONCAT( ROUND( (#bytes/1048576), 2 ), ' MB')
WHEN ABS(#bytes) < 1099511627776 THEN CONCAT( ROUND( (#bytes/1073741824), 2 ), ' GB' )
WHEN ABS(#bytes) < 1125899906842624 THEN CONCAT( ROUND( (#bytes/1099511627776), 2 ), ' TB')
WHEN ABS(#bytes) < 1152921504606846976 THEN CONCAT( ROUND( (#bytes/1125899906842624), 2 ), ' PB' )
WHEN ABS(#bytes) < 1180591620717411303424 THEN CONCAT( ROUND( (#bytes/1152921504606846976) ,2), ' EB' )
WHEN ABS(#bytes) < 1208925819614629174706176 THEN CONCAT( ROUND( (#bytes/1180591620717411303424), 2), ' ZB' )
WHEN ABS(#bytes) < 1237940039285380274899124224 THEN CONCAT( ROUND( (#bytes/1208925819614629174706176), 2), ' YB' )
WHEN ABS(#bytes) < 1267650600228229401496703205376 THEN CONCAT( ROUND( (#bytes/1237940039285380274899124224), 2), ' BB' )
END

Answer 1

I know this is an old question, but I was looking for the same thing recently, and found out that MySQL 5.7 added format_bytes function exactly for this purpose:
mysql> SELECT format_bytes(512), format_bytes(18446644073709551615);
+-------------------+------------------------------------+
| format_bytes(512) | format_bytes(18446644073709551615) |
+-------------------+------------------------------------+
| 512 bytes | 16383.91 PiB |
+-------------------+------------------------------------+

Answer 2

I have a more elegant solution (also using a user defined function):
CREATE FUNCTION `format_filesize`(filesize FLOAT) RETURNS varchar(20) CHARSET utf8
BEGIN
DECLARE n INT DEFAULT 1;
LOOP
IF filesize < 1024 THEN
RETURN concat(round(filesize, 2), ' ', elt(n, 'Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB', 'BB'));
END IF;
SET filesize = filesize / 1024;
SET n = n + 1;
END LOOP;
END
UPDATE:
Even better, and can be used outside procedures:
SET #filesize = 536870912;
SET #log = IFNULL(TRUNCATE(LOG(1024, #filesize), 0),0);
SELECT CONCAT(ROUND(#filesize / POW(1024, #log), 2), ' ',
ELT(#log + 1, 'Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB', 'BB'));

Answer 3

Renaat's code is failing when filesize is 0 (obviously you can't do LOG from zero). Therefore #log is filled with null and CONCAT produce null as well.
Correct fix is:
SET #filesize = 536870912;
SET #log = IFNULL(TRUNCATE(LOG(1024, #filesize), 0),0);
SELECT CONCAT(ROUND(#filesize / POW(1024, #log), 2), ' ',
ELT(#log + 1, 'Bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB', 'BB'));

Answer 4

select concat(round(data*1048576/1073741824,2),' GB')
for example: 1024 = 1gb
select concat(round(1024*1048576/1073741824,2),' GB')
1gb

Answer 5

The top answer about using format_bytes, despite being answered in 2016, is sadly still not found in MariaDB.
I adapted the query from here to make a function I could use.
FUNCTION `format_bytes`(val float) RETURNS varchar(20) CHARSET latin1
BEGIN
DECLARE pw smallint;
IF val < 1024 THEN
return CONCAT(val, ' B');
END IF;
SET pw = LEAST(7, FLOOR(LOG(val) / LOG(1024)));
RETURN CONCAT(ROUND(val / POW(1024, pw), 2), ' ', SUBSTR('KMGTPEZY', pw, 1), 'B');
END
>>> SELECT format_bytes(512), format_bytes(18446644073709551615);
+-------------------+------------------------------------+
| format_bytes(512) | format_bytes(18446644073709551615) |
+-------------------+------------------------------------+
| 512 B | 16.00 EB |
+-------------------+------------------------------------+
A few things could be tweaked to more closely mimic the MySQL format_bytes, but it's not what I was aiming for.