Controlling the national collating sequence with a locale

You can use national literals or data items of USAGE NATIONAL in a relation condition with any relational operator. The PROGRAM COLLATING SEQUENCE clause has no effect on comparisons that involve national operands.

Use the NCOLLSEQ(LOCALE) compiler option to effect comparisons based on the algorithm for collation order that is associated with the active locale at run time. If NCOLLSEQ(BINARY) is in effect, the collating sequence is determined by the binary values of the national characters.

Keys used in a SORT or MERGE statement can be class national only if the NCOLLSEQ(BIN) option is in effect.

related references  
NCOLLSEQ  
Classes and categories of data (COBOL for AIX Language Reference)  
National comparisons (COBOL for AIX Language Reference)