SQL Help Reqd.

Question

Hi All,
I have following requirement:
Table Name: CUSTOMER
Fields in this table: CUSTOMER_ID, TAG, SUBFIELD, VALUE
When TAG = '100' and SUBFIELD = 'a' VALUE represents Customer created date.
When TAG = '200' and SUBFIELD = 'a' VALUE represents Customer changed date.
When TAG = '300' and SUBFIELD = 'a' VALUE represents Customer birth date.
When TAG = '400' and SUBFIELD = 'a' VALUE represents Customer zip code.
Table Name: CUSTOMER2
Fields in this table: CUSTOMER_ID, FIRST_NAME, LAST_NAME
Now I want all the CUSTOMER_ID whose created date >= Todays date and changed date >= Todays date.
For all the above CUSTOMER_ID I want to retrieve CUSTOMER2-FIRST_NAME, CUSTOMER2-LAST_NAME, birth date and zip code in a CSV file.
Can some one please help me with the SQL Code for the above logic,
Thanks in advance,
Raja

Answer 1

Example...
Without the max and group by...
SQL> ed
Wrote file afiedt.buf
  1  with t as (select 1 as cust_id, 'x' as category, 10 as value from dual union all
  2             select 1, 'y', 20 from dual union all
  3             select 1, 'z', 30 from dual union all
  4             select 2, 'x', 40 from dual union all
  5             select 2, 'y', 50 from dual union all
  6             select 2, 'z', 60 from dual)
  7  -- END OF TEST DATA
  8  select cust_id
  9        ,case when category = 'x' then value else null end as x
10        ,case when category = 'y' then value else null end as y
11        ,case when category = 'z' then value else null end as z
12  from t
13* order by cust_id, x, y, z
SQL> /
   CUST_ID          X          Y          Z
         1         10
         1                    20
         1                               30
         2         40
         2                    50
         2                               60
6 rows selected.As you can see the data has been put in the right columns but it's still split into individual rows.
So using the max and group by we can get all the data on one row for each cust_id...
SQL> ed
Wrote file afiedt.buf
  1  with t as (select 1 as cust_id, 'x' as category, 10 as value from dual union all
  2             select 1, 'y', 20 from dual union all
  3             select 1, 'z', 30 from dual union all
  4             select 2, 'x', 40 from dual union all
  5             select 2, 'y', 50 from dual union all
  6             select 2, 'z', 60 from dual)
  7  -- END OF TEST DATA
  8  select cust_id
  9        ,max(case when category = 'x' then value else null end) as x
10        ,max(case when category = 'y' then value else null end) as y
11        ,max(case when category = 'z' then value else null end) as z
12  from t
13  group by cust_id
14* order by cust_id
SQL> /
   CUST_ID          X          Y          Z
         1         10         20         30
         2         40         50         60
SQL>;)