select value from same row using case on table oracle
<p>I have a table like that in oracle:</p>

<p><a href="https://i.stack.imgur.com/QkiZb.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QkiZb.jpg" alt="enter image description here"></a></p>

<p>Then I want to select customer_type and my new column named 'customer_id'. If customer_type is 'CORPORATE' then 'customer_id' column will filled with shipper_id else if customer_type is 'RETAIL' the column ('customer_id') will filled with shipper_phone.</p>

<p>This is my query:</p>

<pre><code>select 
shipper_id,
shipper_name, 
customer_type,
case customer_type when 'RETAIL' then shipper_phone
when 'CORPORATE' then shipper_id
else 'Y'
from 
connote c 
inner join 
mst_customer mc 
on c.shipper_id = mc.customer_id ;
</code></pre>