Get data type of field in select statement in ORACLE

Question

Can I get data types of each column I selected instead of the values, using a select statement?

FOR EXAMPLE:

SELECT a.name, a.surname, b.ordernum  FROM customer a JOIN orders b ON a.id = b.id 

and result should be like this

name    | NVARCHAR(100) surname | NVARCHAR(100) ordernum| INTEGER 

or it can be in row like this, it isn't important:

name           |   surname     |  ordernum NVARCHAR(100)  | NVARCHAR(100) |   INTEGER 

Thanks

Answer 1

I found a not-very-intuitive way to do this by using DUMP()

SELECT DUMP(A.NAME),         DUMP(A.surname),         DUMP(B.ordernum)  FROM   customer A         JOIN orders B           ON A.id = B.id 

It will return something like:

'Typ=1 Len=2: 0,48' for each column.

Type=1 means VARCHAR2/NVARCHAR2
Type=2 means NUMBER/FLOAT
Type=12 means DATE, etc.

You can refer to this oracle doc for information Datatype Code
or this for a simple mapping Oracle Type Code Mappings