UUID : Unique value or different ones ?

[Jean-Nicolas BERGER]

Hi,

When I execute
SELECT X,X as Y FROM (SELECT UUID() AS X) t;
I get the same value for both columns (X and Y)

But when I execute
SELECT X,X AS Y FROM (SELECT UUID() AS X FROM (SELECT 1 AS ZZ) z) t;
I still get one row but X and Y columns have different values.

Could someone explain it ?

Regards.
JN.