COBOL Sorting

Any in-memory sorting that is performed by using COBOL functions is performed as a binary sort in the current character encoding that is used for COBOL processing and may not necessarily match the sort order that is returned by the database in response to an ORDER BY clause. If you require the database to return data that is sorted by using a binary sort of its encoding rather than the default linguistically correct sort, you must use the %BINARYSORT meta-Structured Query Language (meta-SQL) function around each column in the WHERE or ORDER BY clause where binary ordering is important.

However, for DB2 UDB for OS/390 and z/OS implementations, this binary sorting is equivalent only when the COBOL program is run on a DB2 UDB for OS/390 and z/OS server. For example, the binary sort that is produced in COBOL differs from the binary sort that is produced by the database, because the database is encoded in EBCDIC and the client is in an ASCII-based encoding. Therefore, use the %BINARYSORT meta-SQL function only in COBOL programs that are not run through RemoteCall (the DB2 UDB for OS/390 and z/OS platform is not supported as a RemoteCall server).

When running against non-z/OS systems, the %BINARYSORT function can be used in both RemoteCall and non-RemoteCall programs.

For example:

SELECT RECNAME FROM PSRECDEFN  WHERE %BINARYSORT(RECNAME) < %BINARYSORT('xxx')
SELECT RECNAME FROM PSRECDEFN  ORDER BY %BINARYSORT(RECNAME)

Note:

Using the %BINARYSORT Meta-SQL token in WHERE and ORDER BY clauses often negates the use of any indexes, because most databases can't use indexes for functional comparisons (for example, WHERE %BINARYSORT(column) > 'X'). Use this syntax only when sorting equivalence of SQL statement results and when COBOL memory order is absolutely required.