Using a variable in another variable

[Questvba]

Hello,
I hope everyone is well. Thank you for welcoming me for my first post.

In sql developer, I can use this syntax which allows me to define a variable containing another variable:

define V1= 10
define V2= 10 + &&V1

select 
    &&V1
    ,&&V2
from dual
;

With DBeaver, I try in all directions but I don't get anywhere. My last attempt :

@set V1 = 5
@set V2 = 10 + :V1

SELECT 
	:V1
	,:V2
FROM dual;

An error : SQL Error [1008] [72000]: ORA-01008
Can you tell me how I should proceed? Many thanks for all the information.

[Questvba]

After several tests, this seems to work

@set V1 = 5
@set V2 = 10 + ${V1}

SELECT 
	:V1
	,:V2
FROM dual;

Can anyone tell me what the use of ${ } means?

[jmoraleda]

${varName} is an alternative syntax for :varName https://github.com/dbeaver/dbeaver/wiki/SQL-Execution#variables-binding. The ${} syntax replaces the variable in some contexts where the the colon (:) syntax would not be replaced, such as inside strings or inside the value of other variables.

For example:

@set V1 = 5
@set V2 = 10 + :V1
@set V3= 10 + ${V1}
@echo "V2" equals "${V2}" and "V3" equals "${V3}"

prints "V2" equals "10 + :V1" and "V3" equals "10 + 5"