https://jingyan.baidu.com/article/ce09321bbe95d92bfe858f6e.html
https://www.cnblogs.com/piperck/p/5131289.htmlhttps://note.youdao.com/ynoteshare1/index.html?id=66f200a57b2494871c6dac866f078bf0&type=note
MySQL 千万 级数据量根据(索引)优化 查询 速度https://www.cnblogs.com/phpdragon/p/8231533.html
SELECT app.app_key as appKey,d.account_child_balance AS 子账本余额, d.policy AS 计费类型, d.discount AS 正在执行折扣率, d.discount_start_time AS 折扣开始时间, d.discount_end_time AS 折扣结束时间, CASE WHEN app.status = 0 THEN '创建' WHEN app.status = 3 THEN '已上线' WHEN app.status = 5 THEN '封禁' WHEN app.st...