场景：

• 我想将openid字段和order_no字段前后保留4个字符，中间部分无论多长都用“******”进行替换掉，我应该怎么写sql？

示例：

SELECT 
    CONCAT(
        SUBSTRING(openid, 1, 4), 
        '******', 
        SUBSTRING(openid, LENGTH(openid) - 3, 4)
    ) AS masked_openid,
    CONCAT(
        SUBSTRING(order_no, 1, 4), 
        '******', 
        SUBSTRING(order_no, LENGTH(order_no) - 3, 4)
    ) AS masked_order_no
FROM 
    user_order;

效果：

结论：效果拉满，记得点赞