A challenging dynamic SQL query problem

Question

hi All,
I have a very interesting problem at work:
We have this particular table defined as follows :
CREATE TABLE sales_data (
sales_id NUMBER,
sales_m01 NUMBER,
sales_m02 NUMBER,
sales_m03 NUMBER,
sales_m04 NUMBER,
sales_m05 NUMBER,
sales_m06 NUMBER,
sales_m07 NUMBER,
sales_m08 NUMBER,
sales_m09 NUMBER,
sales_m10 NUMBER,
sales_m11 NUMBER,
sales_m12 NUMBER,
sales_prior_yr NUMBER );
The columns 'sales_m01 ..... sales_m12' represents aggregated monthly sales, in which 'sales_m01' translates to 'sales for the month of january, january being the first month, 'sales_m02' sales for the month of february, and so on.
The problem I face is that we have a project which requires that a parameter be passed to a stored procedure which stands for the month number which is then used to build a SQL query with the following required field aggregations, which depends on the parameter passed :
Sample 1 : parameter input: 4
Dynamically-built SQL query should be :
SELECT
SUM(sales_m04) as CURRENT_SALES,
SUM(sales_m01+sales_m02+sales_m03+sales_m04) SALES_YTD
FROM
sales_data
WHERE
sales_id = '0599768';
Sample 2 : parameter input: 8
Dynamically-built SQL query should be :
SELECT
SUM(sales_m08) as CURRENT_SALES,
SUM(sales_m01+sales_m02+sales_m03+sales_m04+
sales_m05+sales_m06+sales_m07+sales_m08) SALES_YTD
FROM
sales_data
WHERE
sales_id = '0599768';
So in a sense, the contents of SUM(sales_m01 ....n) would vary depending on the parameter passed, which should be a number between 1 .. 12 which corresponds to a month, which in turn corresponds to an actual field range on the table itself. The resulting dynamic query should only aggregate those columns/fields in the table which falls within the range given by the input parameter and disregards all the remaining columns/fields.
Any solution is greatly appreciated.
Thanks.

Answer 1

Hi another simpler approach is using decode
try like this
SQL> CREATE TABLE sales_data (
  2  sales_id NUMBER,
  3  sales_m01 NUMBER,
  4  sales_m02 NUMBER,
  5  sales_m03 NUMBER,
  6  sales_m04 NUMBER,
  7  sales_m05 NUMBER,
  8  sales_m06 NUMBER,
  9  sales_m07 NUMBER,
10  sales_m08 NUMBER,
11  sales_m09 NUMBER,
12  sales_m10 NUMBER,
13  sales_m11 NUMBER,
14  sales_m12 NUMBER,
15  sales_prior_yr NUMBER );
Table created.
SQL> select * from sales_data;
  SALES_ID  SALES_M01  SALES_M02  SALES_M03  SALES_M04  SALES_M05  SALES_M06  SALES_M07  SALES_M08  SALES_M09  SALES_M10  SALES_M11  SALES_M12 SALES_PRIOR_YR
         1        124        123        145        146        124        126        178        189        456        235        234        789          19878
         2        124        123        145        146        124        126        178        189        456        235        234        789          19878
         1        100        200        300        400        500        150        250        350        450        550        600        700          10000
         1        101        201        301        401        501        151        251        351        451        551        601        701          10000----now for your requirement. see below query if there is some problem then tell.
SQL> SELECT sum(sales_m&input_data), DECODE (&input_data,
  2                 1, SUM (sales_m01),
  3                 2, SUM (sales_m01 + sales_m02),
  4                 3, SUM (sales_m01 + sales_m02 + sales_m03),
  5                 4, SUM (sales_m01 + sales_m02 + sales_m03 + sales_m04),
  6                 5, SUM (sales_m01 + sales_m02 + sales_m03 + sales_m04 + sales_m05),
  7                 6, SUM (sales_m01 + sales_m02 + sales_m03 + sales_m04+sales_m05+sales_m06),
  8                 7, SUM (sales_m01 + sales_m02 + sales_m03 + sales_m04+sales_m05+sales_m06+sales_m07),
  9                 8, SUM (sales_m01 + sales_m02 + sales_m03 + sales_m04+sales_m05+sales_m06+sales_m07+sales_m08),
10                 9, SUM (sales_m01 + sales_m02 + sales_m03 + sales_m04+sales_m05+sales_m06+sales_m07+sales_m08+sales_m09),
11                 10,SUM (sales_m01 + sales_m02 + sales_m03 + sales_m04+sales_m05+sales_m06+sales_m07+sales_m08+sales_m09+sales_m10),
12                 11,SUM (sales_m01 + sales_m02 + sales_m03 + sales_m04+sales_m05+sales_m06+sales_m07+sales_m08+sales_m09+sales_m10+sales_m11),
13                 12,SUM (sales_m01 + sales_m02 + sales_m03 + sales_m04+sales_m05+sales_m06+sales_m07+sales_m08+sales_m09+sales_m10+sales_m11+sales_m12)
14                ) total
15    FROM sales_data
16   WHERE sales_id = 1;
Enter value for input_data: 08
Enter value for input_data: 08
old   1: SELECT sum(sales_m&input_data), DECODE (&input_data,
new   1: SELECT sum(sales_m08), DECODE (08,
SUM(SALES_M08)      TOTAL
           890       5663