MySQL order by primary key

Question

Some SQL servers allow for a generic statement such as ORDER BY PRIMARY KEY. I don't believe this works for MySQL, is there any such workaround that would allow for automated selects across multiple tables or does it require a lookup query to determine the primary key?

The workaround I have been working on involves calling a SHOW COLUMNS FROM before running the query. Is there a more efficient way of doing this? Can MySQL determine the primary key of a table during the select process?

Update: There is no official way of doing this in MySQL or SQL in general as Gordon pointed out. SAP has custom functionality for it. There are workarounds, such as working with SHOW COLUMNS FROM table or the information_schema as John pointed out.

Answer 1

MySQL generally pulls data out by insertion order which would be by primary key, but that aside you technically can do the same thing if you pull out the primary key column name and put it in an order by

SELECT whatever FROM table
ORDER BY
(   SELECT `COLUMN_NAME`
    FROM `information_schema`.`COLUMNS`
    WHERE (`TABLE_SCHEMA` = 'dbName')
      AND (`TABLE_NAME` = 'tableName')
      AND (`COLUMN_KEY` = 'PRI')
);

For composite keys you can use this

SELECT whatever FROM table
ORDER BY
(   SELECT GROUP_CONCAT(`COLUMN_NAME` SEPARATOR ', ')
    FROM `information_schema`.`COLUMNS`
    WHERE (`TABLE_SCHEMA` = 'dbName')
      AND (`TABLE_NAME` = 'tableName')
      AND (`COLUMN_KEY` = 'PRI')
);

Permission for information schema access from the DOCS

Each MySQL user has the right to access these tables, but can see only the rows in the tables that correspond to objects for which the user has the proper access privileges. In some cases (for example, the ROUTINE_DEFINITION column in the INFORMATION_SCHEMA.ROUTINES table), users who have insufficient privileges see NULL. These restrictions do not apply for InnoDB tables; you can see them with only the PROCESS privilege.

The same privileges apply to selecting information from INFORMATION_SCHEMA and viewing the same information through SHOW statements. In either case, you must have some privilege on an object to see information about it.

SETUP:

CREATE TABLE some_stuff (
    firstID INT,
    secondID INT,
    username varchar(55),
    PRIMARY KEY (firstID, secondID)
) ;

QUERY:

SELECT GROUP_CONCAT(`COLUMN_NAME` SEPARATOR ', ')
FROM `information_schema`.`COLUMNS`
WHERE (`TABLE_SCHEMA` = 'dbName')
  AND (`TABLE_NAME` = 'some_stuff')
  AND (`COLUMN_KEY` = 'PRI');

OUTPUT:

+--------------------------------------------+
| GROUP_CONCAT(`COLUMN_NAME` SEPARATOR ', ') |
+--------------------------------------------+
|              firstID, secondID             |
+--------------------------------------------+