Mimimum balance

Question

here is the table structure for storing the transaction of cretain a/c holders.
br_daily_depo
trans_cd varchar2(3)
day_dt date
depo_accno number(8)
credit number(14,2)
debit number(14,2)
VERSION ORACLE 8.1.6
for maintaining the details of deposit holders. here i had not included a field for
storing the balance. i need to find the minimum of balace between two given dates.
(balance is (credit) -(debit) for each transaction )
following is the example of data . here i had also displayed the balace of
each transacion. in this the minimum balance is 60 and the date is 22-aug-2002.
trans_cd     day_dtdepo_accno|credit debit     |balance (not a database field)
1000|01-aug-2002|10012 1000          1000     
1000|02-aug-2002|10012           50     950     
1000|03-aug-2002|10012          40     910
1000|03-aug-2002|10012 200          1110
1000|05-aug-2002|10012 1000          2110
1000|05-aug-2002|10012      100     2010     
1000|11-aug-2002|10012 1000          3010
1000|22-aug-2002|10012      50          3060
1000|18-aug-2002|10012      2000     1060     
1000|22-aug-2002|10012      1000     60
1000|30-aug-2002|10012 1000          1060     
1000|31-aug-2002|10012      50     1010
now i am finding the minimum balance by inserting credit, debit and balace of each transaction to a temporary
table and then finding the min(balance) . but this is time consuming.
can i achieve the same by using a single query.
sincerely
raj

Answer 1

Although you only included one value for trans_cd in your sample data, I am assuming that you have many trans_cd values and that you want the minimum running balance for each trans_cd, so I added some additional data in the example below. I have included a query to show the test data and a query to show the running balance, but all you need is the last query to get the minimum running balance for each trans_cd.
SQL> -- test data:
SQL> SELECT * FROM br_daily_depot
  2  /
TRAN DAY_DT      DEPO_ACCNO     CREDIT      DEBIT
1000 01-aug-2002      10012       1000
1000 02-aug-2002      10012                    50
1000 03-aug-2002      10012                    40
1000 03-aug-2002      10012        200
1000 05-aug-2002      10012       1000
1000 05-aug-2002      10012                   100
1000 11-aug-2002      10012       1000
1000 12-aug-2002      10012         50
1000 18-aug-2002      10012                  2000
1000 22-aug-2002      10012                  1000
1000 30-aug-2002      10012       1000
1000 31-aug-2002      10012                    50
1001 18-aug-2002      10013       2000
1001 30-aug-2002      10013       1000
1001 31-aug-2002      10013                    50
15 rows selected.
SQL>
SQL>
SQL> -- query to get running balance:
SQL> SELECT      trans_cd, day_dt, depo_accno, credit, debit,
  2           SUM (NVL (credit, 0) - NVL (debit, 0)) OVER
  3               (PARTITION BY trans_cd ORDER BY day_dt) AS balance
  4  FROM        br_daily_depot
  5  /
TRAN DAY_DT      DEPO_ACCNO     CREDIT      DEBIT    BALANCE
1000 01-aug-2002      10012       1000                  1000
1000 02-aug-2002      10012                    50        950
1000 03-aug-2002      10012                    40        910
1000 03-aug-2002      10012        200                  1110
1000 05-aug-2002      10012       1000                  2010
1000 05-aug-2002      10012                   100       2010
1000 11-aug-2002      10012       1000                  3010
1000 12-aug-2002      10012         50                  3060
1000 18-aug-2002      10012                  2000       1060
1000 22-aug-2002      10012                  1000         60
1000 30-aug-2002      10012       1000                  1060
1000 31-aug-2002      10012                    50       1010
1001 18-aug-2002      10013       2000                  2000
1001 30-aug-2002      10013       1000                  3000
1001 31-aug-2002      10013                    50       2950
15 rows selected.
SQL>
SQL>
SQL> -- query to get minimum running balance for each trans_cd:
SQL> SELECT      trans_cd, day_dt, depo_accno, balance
  2  FROM        (SELECT        trans_cd, day_dt, depo_accno, balance,
  3                     RANK () OVER (PARTITION BY trans_cd ORDER BY balance) AS rk
  4            FROM     (SELECT   trans_cd, day_dt, depo_accno, credit, debit,
  5                               SUM (NVL (credit, 0) - NVL (debit, 0)) OVER
  6                                   (PARTITION BY trans_cd ORDER BY day_dt) AS balance
  7                      FROM     br_daily_depot))
  8  WHERE       rk = 1
  9  /
TRAN DAY_DT      DEPO_ACCNO    BALANCE
1000 22-aug-2002      10012         60
1001 18-aug-2002      10013       2000