Index example: Ordering and grouping on different columns with ALWCPYDTA(*OPTIMIZE) and a unique-weight sort sequence table

 

Ordering and grouping on different columns with ALWCPYDTA(*OPTIMIZE) and a unique-weight sort sequence table (SRTSEQ(*LANGIDUNQ) LANGID(ENU)).

  SELECT JOB, SALARY FROM STAFF    GROUP BY JOB, SALARY    ORDER BY SALARY, JOB

When using the OPNQRYF command, specify:

OPNQRYF FILE((STAFF)) FORMAT(FORMAT3)
   GRPFLD(JOB SALARY)
   KEYFLD(SALARY JOB)
   SRTSEQ(*LANGIDUNQ) LANGID(ENU)
   ALWCPYDTA(*OPTIMIZE)

The system can use index HEXIX2 or index UNQIX2 to satisfy the grouping requirements. A sort is performed to satisfy the ordering requirements.

 

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Examples of indexes