easier way to get the result as shown by following sql query (oracle database)

Question

Can anybody let us know an easier way to get the result as shown by following query? We need to find a way that can show us the same result as the following query:

SELECT  DISTINCT A.bio_id ,
    DECODE(A.wk_units2 - B.wk_units1,0,NULL,A.wk_units2) prev,
    DECODE(A.wk_units2 - B.wk_units1,0,NULL,B.wk_units1) curr, 
    DECODE(A.wk_units3 -B.wk_units2,0,NULL,A.wk_units3) prev, 
    DECODE(A.wk_units3 -B.wk_units2,0,NULL,B.wk_units2) curr, 
    DECODE(A.wk_units4 -B.wk_units3,0,NULL,A.wk_units4) prev, 
    DECODE(A.wk_units4 -B.wk_units3,0,NULL,B.wk_units3) curr,
    DECODE(A.wk_units5 -B.wk_units4,0,NULL,A.wk_units5) prev, 
    DECODE(A.wk_units5 -B.wk_units4,0,NULL,B.wk_units4) curr, 
    DECODE(A.wk_units6 -B.wk_units5,0,NULL,A.wk_units6) prev, 
    DECODE(A.wk_units6 -B.wk_units5,0,NULL,B.wk_units5) curr 
     .                                            .
     .                                            .
     .                                            .
   DECODE(A.wk_units105 -B.wk_units104,0,NULL,A.wk_units105) prev, 
   DECODE(A.wk_units105 -B.wk_units105,0,NULL,B.wk_units104) curr 



    FROM 
    cnt_sls_dm.fct_sales_summary A,
    cnt_sls_dm.fct_sales_summary B 
    WHERE 
    A.bio_id=B.bio_id AND A.bio_id<>0 
    AND ROWNUM<25 
    AND ( A.wk_units2<> B.wk_units1 
    OR  A.wk_units3<> B.wk_units2 
    OR  A.wk_units4<> B.wk_units3 
    OR  A.wk_units5<> B.wk_units4 
    OR  A.wk_units6<> B.wk_units5
     .                        .
     .                        .
     .                        .
    OR  A.wk_units105<>B.wk_units104)

The output is like:

    BIO_ID  PREV CURR PREV_1 CURR_1 PREV_2 CURR_2 PREV_3 CURR_3
5,032,130.00    -1 0 0 1   0 1
5,032,130.00    1 0 0 1 1 0 0 1
5,032,130.00      0 1   0 1
5,032,130.00      10 1 10 0 0 1
5,032,328.00    53 0 36 0 20 0  
5,032,328.00          1 0
5,175,147.00    2 0      
5,175,147.00      2 0    
5,175,147.00           
21,073,129.00   17 0     2 0
21,073,129.00   18 0 6 0 2 0  
21,073,129.00         1 0
21,073,129.00         3 0
21,073,129.00

Answer 1

Hi, I'd change the part

AND ( A.wk_units2<> B.wk_units1 
OR  A.wk_units3<> B.wk_units2 
OR  A.wk_units4<> B.wk_units3  ...

to

AND NOT ( A.wk_units2 == B.wk_units1 
OR A.wk_units3== B.wk_units2 
...

as it may be faster. But I've no idea to circumvent the DECODE stuff.