Question

I am trying to write a query that will give me the max date form Table_A based on the following condition.

If the given date (input parameter) falls between 01 April and 30 Sept of that year then return MAX(date) prior to April 1.

OR

If the given date (input parameter) falls between 01 Oct and 31 March of the following year then return MAX(date) prior to Oct 1.

For example :

1. Given date is 27th Dec, 2012 (date between 01 Oct and 31 March of the following year)
   return 29th Sept, 2012
2. Given Date is 17th Aug, 2012 (date between 01 April and 30 Sept of the following year)
   return date (MAX DATE prior to is 01 April is 29th March)

Answer 1

try this:

select max(case
            when trunc(the_date) between to_date('01-apr-'||the_year, 'dd-mon-yyyy')
                                     and to_date('30-sep-'||the_year, 'dd-mon-yyyy')
             and dte < to_date('01-apr-'||the_year, 'dd-mon-yyyy')
            then
              dte
            when trunc(the_date) between to_date('01-oct-'||the_year, 'dd-mon-yyyy')
                                     and to_date('31-mar-'||(the_year+1), 'dd-mon-yyyy')
             and dte < to_date('01-oct-'||the_year, 'dd-mon-yyyy')
            then
              dte
           end) max_date
  from table_a a 
       cross join (select v_inp_date the_date,
                          to_char(add_months(v_inp_date,-3), 'yyyy') the_year
                     from dual) dte;

so you input date is in the dte part

v_inp_date

and

 to_char(add_months(v_inp_date,-3), 'yyyy') the_year

eg a small test:

SQL> create table table_a(dte date);

    Table created.

SQL> insert into table_a values(to_date('28-sep-2012', 'dd-mon-yyyy'));

1 row created.

SQL> insert into table_a values(to_date('29-sep-2012', 'dd-mon-yyyy'));

1 row created.

SQL> insert into table_a values(to_date('28-mar-2012', 'dd-mon-yyyy'));

1 row created.

SQL> insert into table_a values(to_date('29-mar-2012', 'dd-mon-yyyy'));

1 row created.

SQL> insert into table_a values(to_date('28-sep-2011', 'dd-mon-yyyy'));

1 row created.

SQL> insert into table_a values(to_date('27-mar-2011', 'dd-mon-yyyy'));

1 row created.

SQL> commit;

Commit complete.

SQL> var inpdate varchar2(20);
SQL> exec :inpdate := '27-dec-2012';

PL/SQL procedure successfully completed.

SQL> select max(case
  2              when trunc(the_date) between to_date('01-apr-'||the_year, 'dd-mon-yyyy')
  3                                       and to_date('30-sep-'||the_year, 'dd-mon-yyyy')
  4               and dte < to_date('01-apr-'||the_year, 'dd-mon-yyyy')
  5              then
  6                dte
  7              when trunc(the_date) between to_date('01-oct-'||the_year, 'dd-mon-yyyy')
  8                                       and to_date('31-mar-'||(the_year+1), 'dd-mon-yyyy')
  9               and dte < to_date('01-oct-'||the_year, 'dd-mon-yyyy')
 10              then
 11                dte
 12             end) max_date
 13    from table_a a
 14         cross join (select to_date(:inpdate,'dd-mon-yyyy') the_date,
 15                            to_char(add_months(to_date(:inpdate,'dd-mon-yyyy'), -3), 'yyyy') the_year
 16                       from dual) dte;

MAX_DATE
---------
29-SEP-12

SQL> exec :inpdate := '17-aug-2012';

PL/SQL procedure successfully completed.

SQL> /

MAX_DATE
---------
29-MAR-12

SQL> exec :inpdate := '01-oct-2011';

PL/SQL procedure successfully completed.

SQL> /

MAX_DATE
---------
28-SEP-11

SQL> exec :inpdate := '01-apr-2011';

PL/SQL procedure successfully completed.

SQL> /

MAX_DATE
---------
27-MAR-11

SQL>