Date rage count

Question

HI
Need some help in this SQL
WITH EMP_TAB AS(
SELECT 1 EMPID, to_date('30-Mar-2011','dd-MON-yyyy') D from dual union all
SELECT 1 EMPID, to_date('24-Mar-2011','dd-MON-yyyy') D from dual union all
SELECT 1 EMPID, to_date('23-Mar-2011','dd-MON-yyyy') D from dual union all
SELECT 1 EMPID, to_date('22-Mar-2011','dd-MON-yyyy') D from dual union all
SELECT 1 EMPID, to_date('20-Mar-2011','dd-MON-yyyy') D from dual union all
SELECT 1 EMPID, to_date('18-Mar-2011','dd-MON-yyyy') D from dual union all
SELECT 3 EMPID, to_date('17-Mar-2011','dd-MON-yyyy') D from dual
) SELECT * FROM EMP_TAB;here in this table When I pass parameter as empid=1 and D as '25-Mar-2011' The query should check the number of continuous dates starting from 24-Mar-2011
So the result should return, as we have 3 dates from 24th to 22nd
EMPID RANGE
1        3Edited by: Prasath on 29-Mar-2011 07:07

Answer 1

Hi SY.
The one with analytical function doesnt work if you have duplicate dates.
SQL> WITH EMP_TAB AS(
  2                  SELECT 1 EMPID, TO_DATE('30-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  3                  SELECT 1 EMPID, TO_DATE('24-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  4                  SELECT 1 EMPID, TO_DATE('22-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  5                  SELECT 1 EMPID, TO_DATE('22-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  6                  SELECT 1 EMPID, TO_DATE('20-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  7                  SELECT 1 EMPID, TO_DATE('18-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  8                  SELECT 3 EMPID, TO_DATE('17-Mar-2011','dd-MON-yyyy') D FROM dual
  9                 )
10  SELECT 1 EMPID, MAX (RN)
11    FROM (SELECT D, ROW_NUMBER () OVER (ORDER BY D DESC) RN
12            FROM EMP_TAB
13           WHERE EMPID = 1
14             AND D < DATE '2011-03-25')
15   WHERE D = DATE '2011-03-25' - RN;
     EMPID    MAX(RN)
         1          3
SQL>
The result should be 1.. but got 3.
Dense rank should work
SQL> WITH EMP_TAB AS(
  2                  SELECT 1 EMPID, TO_DATE('30-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  3                  SELECT 1 EMPID, TO_DATE('24-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  4                  SELECT 1 EMPID, TO_DATE('22-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  5                  SELECT 1 EMPID, TO_DATE('22-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  6                  SELECT 1 EMPID, TO_DATE('20-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  7                  SELECT 1 EMPID, TO_DATE('18-Mar-2011','dd-MON-yyyy') D FROM dual UNION ALL
  8                  SELECT 3 EMPID, TO_DATE('17-Mar-2011','dd-MON-yyyy') D FROM dual
  9                 )
10  SELECT 1 EMPID, MAX (RN)
11    FROM (SELECT D, DENSE_RANK () OVER (ORDER BY D DESC) RN
12            FROM EMP_TAB
13           WHERE EMPID = 1
14             AND D < DATE '2011-03-25')
15   WHERE D = DATE '2011-03-25' - RN;
     EMPID    MAX(RN)
         1          1
SQL> G.