Oracle 18c

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CREATE TABLE table_name
(
  id     INT GENERATED ALWAYS AS IDENTITY
         NOT NULL
         CONSTRAINT table_name__id__pk PRIMARY KEY,
  userid VARCHAR2(11)
         GENERATED ALWAYS AS (
           CAST('UID' || TO_CHAR(id, 'FM00000000') AS VARCHAR2(11))
         ),
  name   VARCHAR2(50)
);
INSERT INTO table_name (name)
SELECT 'Alice' FROM DUAL UNION ALL
SELECT 'Beryl' FROM DUAL UNION ALL
SELECT 'Carol' FROM DUAL;
3 rows affected

SELECT * FROM table_name;


ID
USERID
NAME


1
UID00000001
Alice

2
UID00000002
Beryl

3
UID00000003
Carol