mysql sql转换oracle

-- MySQL
CREATE TABLE users (
    id INT PRIMARY KEY,
    name VARCHAR(255)
);

-- Oracle
CREATE TABLE users (
    id NUMBER PRIMARY KEY,
    name VARCHAR2(255)
);

-- MySQL
SELECT CONCAT('Hello', ' ', 'World');

-- Oracle
SELECT 'Hello' || ' ' || 'World' FROM dual;

-- MySQL
DELIMITER //
CREATE PROCEDURE get_user(IN user_id INT)
BEGIN
    SELECT * FROM users WHERE id = user_id;
END //
DELIMITER ;

-- Oracle
CREATE OR REPLACE PROCEDURE get_user(user_id IN NUMBER)
IS
BEGIN
    SELECT * FROM users WHERE id = user_id;
END;

-- MySQL
SELECT * FROM users ORDER BY id LIMIT 10 OFFSET 20;

-- Oracle
SELECT * FROM (
    SELECT a.*, ROWNUM rnum FROM (
        SELECT * FROM users ORDER BY id
    ) a
    WHERE ROWNUM <= 30
)
WHERE rnum > 20;