Question

this is my first post here.
I’m working with cheques, i have this in the Oracle 11g database

 WITH cheques AS (
    SELECT 1 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 2 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 3 ch_no,'T' ch_status FROM dual UNION ALL
    SELECT 4 ch_no,'T' ch_status FROM dual UNION ALL
    SELECT 5 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 6 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 7 ch_no,'C' ch_status FROM dual UNION ALL
    SELECT 8 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 9 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 10 ch_no,'C' ch_status FROM dual UNION ALL
    SELECT 11 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 12 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 13 ch_no,'X' ch_status FROM dual UNION ALL
    SELECT 14 ch_no,'X' ch_status FROM dual UNION ALL
    SELECT 15 ch_no,'T' ch_status FROM dual UNION ALL
    SELECT 16 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 17 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 18 ch_no,'I' ch_status FROM dual UNION ALL
    SELECT 19 ch_no,'I' ch_status FROM dual UNION ALL
    SELECT 20 ch_no,'U' ch_status FROM dual
 )

I want tho get them in this way:

Status  Min Max
U   1   2
U   5   6
U   8   9
U   11  12
U   16  17
U   20  20
C   7   7
C   10  10
T   3   4
T   15  15
X   13  14
I   18  19

So, In Reporting Services 2008,i will be able to show them like this:

U       C       T       X       I   
Min Max Min Max Min Max Min Max Min Max
1   2   7   7   3   4   13  14  18  19
5   6   10  10  15  15              
8   9                               
11  12                              
16  17                              
20  20      

The question here is how to get this, how to get the min and max of each cheque based on their status?
I have searched, but i couldn’t find anything.

Sorry for my english.

Thanks!

Answer 1

This isn’t a straightforward problem and needs a number of steps.

1. use lag to set a ‘flag’ at the start of each contiguous block of ch_no with the same ch_status
2. use sum as an analytic with an order by (which changes the default window to unbounded preceeding) to give each contiguous block a unique identifier
3. finally use a regular group by to calculate the min & max for each block

Query:

WITH cheques AS (
    SELECT 1 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 2 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 3 ch_no,'T' ch_status FROM dual UNION ALL
    SELECT 4 ch_no,'T' ch_status FROM dual UNION ALL
    SELECT 5 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 6 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 7 ch_no,'C' ch_status FROM dual UNION ALL
    SELECT 8 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 9 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 10 ch_no,'C' ch_status FROM dual UNION ALL
    SELECT 11 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 12 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 13 ch_no,'X' ch_status FROM dual UNION ALL
    SELECT 14 ch_no,'X' ch_status FROM dual UNION ALL
    SELECT 15 ch_no,'T' ch_status FROM dual UNION ALL
    SELECT 16 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 17 ch_no,'U' ch_status FROM dual UNION ALL
    SELECT 18 ch_no,'I' ch_status FROM dual UNION ALL
    SELECT 19 ch_no,'I' ch_status FROM dual UNION ALL
    SELECT 20 ch_no,'U' ch_status FROM dual
 )
select ch_status, min(ch_no), max(ch_no)
from( select ch_no, ch_status, sum(changed_flag) over (order by ch_no) as grp
      from( select ch_no, ch_status, 
                   decode(ch_status,lag(ch_status) over(order by ch_no),0,1) 
                     as changed_flag
            from cheques ) )
group by ch_status, grp
order by ch_status, min(ch_no)

Results:

| CH_STATUS | MIN(CH_NO) | MAX(CH_NO) |
---------------------------------------
|         C |          7 |          7 |
|         C |         10 |         10 |
|         I |         18 |         19 |
|         T |          3 |          4 |
|         T |         15 |         15 |
|         U |          1 |          2 |
|         U |          5 |          6 |
|         U |          8 |          9 |
|         U |         11 |         12 |
|         U |         16 |         17 |
|         U |         20 |         20 |
|         X |         13 |         14 |

SQL Fiddle here