I need the below results ..
Table :
Order postcode qnty
123 2234 1
Expected result:
Order 123
Postcode 2234
Qnty 1
SQL server:
Select pvt.element_name
,pvt.element_value(select order.postcode
from table name)up
unpivot (element_value for element_name in(order,postcode) as Pvt
How to achieve this in db2?
Db2 for IBM i doesn't have a built-in unpviot function.. AFAIK, it's not available on any Db2 platofrm...unless it's been added recently.
The straight forward method
select 'ORDER' as key, order as value
from mytable
UNION ALL
select 'POSTCODE', postcode
from mytable
UNION ALL
select 'QNTY', char(qnty)
from mytable;
A better performing method is to do a cross join between the source table and a correlated VALUES of as many rows as columns that need to be unpivoted.
select
Key, value
from mytable T,
lateral (values ('ORDER', t.order)
, ('POSTCODE', t.postcode)
, ('QNQTY', varchar(t.qnty))
) as unpivot(key, value);
However, you'll need to know ahead of time what the values you're unpivoting on.
If you don't know the values, there are some ways to unpivot with the XMLTABLE (possibly JSON_TABLE) that might work. I've never used them, and I'm out of time to spend answering this question. You can find some examples via google.
I have created a stored procedure for LUW that rotate a table: https://github.com/angoca/db2tools/blob/master/pivot.sql
You just need to call the stored procedure by passing the tablename as parameter, and it will return a cursor with the headers of the column in the first column.
