Naming a default constraint

I’m trying to create a default constraint here, but the system is generating a weird name for it. If I want to name it df_MY_TABLE_GUID or something, how could I specify that name be used?

ALTER TABLE MY_TABLE 
    ADD MY_GUID uniqueidentifier NOT NULL 
        CONSTRAINT uq_MY_TABLE_GUID UNIQUE (MY_TABLE_GUID) 
        DEFAULT NEWID() WITH VALUES

Answer

Just specify the constraint name with the full syntax, like the UNIQUE in your example:

ALTER TABLE MY_TABLE ADD MY_GUID UNIQUEIDENTIFIER NOT NULL
    CONSTRAINT uq_MY_TABLE_GUID UNIQUE (MY_TABLE_GUID)
    CONSTRAINT df_MY_TABLE_GUID DEFAULT NEWID() WITH VALUES ;

As a matter of routine, I always prefer and encourage to always name every single constraint I create, for the sake of easy reference latter on.