-- 必須頂格寫（無縮進）
DELIMITER //
CREATE PROCEDURE grant_role_to_all_users()
BEGIN
    -- 這里面的縮進不會影響執(zhí)行
    DECLARE finished INTEGER DEFAULT 0;
    DECLARE user_host VARCHAR(255);
    
    DECLARE user_cursor CURSOR FOR 
        SELECT CONCAT('`',USER,'`@`',HOST,'`') 
        FROM mysql.user 
        WHERE USER NOT IN ('root','mysql.sys','mysql.session','mysql.infoschema');
    
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET finished = 1;
    
    OPEN user_cursor;
    
    get_user: LOOP
        FETCH user_cursor INTO user_host;
        IF finished = 1 THEN LEAVE get_user; END IF;
        
        SET @grant_sql = CONCAT('GRANT "public_role" TO ', user_host);
        PREPARE stmt FROM @grant_sql;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;
        
        SET @default_sql = CONCAT('SET DEFAULT ROLE "public_role" FOR ', user_host);
        PREPARE stmt FROM @default_sql;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;
    END LOOP get_user;
    
    CLOSE user_cursor;
END//
-- 必須頂格寫（無縮進）
DELIMITER ;

-- 頂格
DELIMITER //
CREATE PROCEDURE proc_name()
BEGIN
    -- 縮進內容
    SELECT * FROM table;
END//
-- 頂格
DELIMITER ;

mysql -u user -p db_name < procedure.sql