From: Sub-Z Pulao on
I am trying to do the equivalent of this Teradata query in Oracle, and
I can't figure it out

select *
from tab
when prod_code = 'AS' then 10
when prod_code = 'CM' then 10
when prod_code = 'DQ' then 10

I got this example from

and was able to adapt it for a specific Teradata query. Now I am
trying to do the same thing in Oracle 10.2.x which has a SAMPLE clause
but not a WHEN subclause. The effect of the WHEN subclause in the
SAMPLE..END block is that it is like doing a "sample 10" for each
value of prod_code (so in the example above, it would return a total
of up to 30 records)

Most of what I'm finding on Google seems to predate Oracle having a
sample clause at all, and it looks like people worked around it using
a subquery and ROWNUM. I thought maybe I needed to adapt one of those
examples so that it supports a sampling for each condition met, but I
was not successful.