how to split single row into multiple row in db2?

Question

This is what i have in table xyz

NAME      AMOUNT      BEGIN_DATE        END_DATE

ABC       5.0        2013-05-11         2014-06-20

following is what i want using IBM DB2 database

NAME      AMOUNT      BEGIN_DATE        END_DATE

ABC        5.0        2013-05-11         2013-12-31

ABC        5.0        2014-01-01         2014-06-30

instead of just one row from xyz table, i need to fetch 2 rows as above output. How do I split one row into two ?

Answer 1

The following will only list rows where the begin and end dates span exactly two years or within the same year.

SELECT 
    NAME,
    AMOUNT,
    BEGIN_DATE,
    DATE(YEAR(BEGIN_DATE)||'-12-31') AS END_DATE
 FROM xyz
 WHERE YEAR(END_DATE)-YEAR(BEGIN_DATE)=1
UNION
SELECT 
    NAME,
    AMOUNT,
    DATE(YEAR(END_DATE)||'-01-01') AS BEGIN_DATE,
    END_DATE
 FROM xyz
 WHERE YEAR(END_DATE)-YEAR(BEGIN_DATE)=1
UNION
SELECT 
    NAME,
    AMOUNT,
    BEGIN_DATE,
    END_DATE
 FROM xyz
 WHERE YEAR(END_DATE)-YEAR(BEGIN_DATE)=0
ORDER BY BEGIN_DATE

Answer 2

You can make two SQL statements, to select the first, using '2013-12-31' as a constant for the end-date, then to select a second time, using '2014-01-01' as a constant start date. Then use UNION ALL to put them together.

If you also have some records that start and end within 2013, and therefore do not need to be split, you can get those separately, and exclude them from the other two queries. Other variations in your data might require some extra conditions, but this example should get you going:

select NAME, AMOUNT, BEGIN_DATE, END_DATE
from xyz
where END_DATE <= '2013-12-31'
UNION ALL
select NAME, AMOUNT, BEGIN_DATE, '2013-12-31'
from xyz
where END_DATE >= '2014-01-01'
UNION ALL
select NAME, AMOUNT, '2014-01-01', END_DATE 
from xyz
where END_DATE >= '2014-01-01'