今天改了 bug，看到了一个 sql，顿时惊了。。。。。 这个是新项目，还没上线这部分内容。。

[luxinfl]

SELECT
a.*
FROM
(
SELECT
a.*
FROM
(
SELECT
a.*
FROM
(
SELECT
a.*
FROM
(
SELECT
a.*
FROM
(
SELECT
PLATFORM_REQUEST_CODE AS platformRequestCode,
AGGTEGATE_REQUEST_CODE AS aggtegateRequestCode,
CREATE_TIME AS createTime,
STATUS AS payStatus,
MERCHANT_GENERATE_CODE AS platformCode,
USER_CODE AS buyCode,
CHANNEL_NO AS channelNo
FROM
tb_aggtegate_payment_request
WHERE
STATUS != '00'
AND DEL_FLAG = 0
AND IS_VALID = 0
ORDER BY
CREATE_TIME DESC
) a
LEFT JOIN ( SELECT CHANNEL_REQUEST_CODE AS channelOrderCode, AGGTEGATE_REQUEST_CODE AS channelaggtegateRequestCode FROM tb_channel_send_report WHERE DEL_FLAG = 0 ) b ON a.aggtegateRequestCode = b.channelaggtegateRequestCode
) a
LEFT JOIN ( SELECT MERCHANT_INFO_CODE, MERCHANT_INFO_NAME AS platformName FROM tb_merchant_info WHERE DEL_FLAG = 0 ) c ON c.MERCHANT_INFO_CODE = a.platformCode
) a
LEFT JOIN ( SELECT PLATFORM_USER_CODE, MERCHANT_NAME AS merchantName FROM tb_user_info WHERE DEL_FLAG = 0 ) b ON a.buyCode = b.PLATFORM_USER_CODE
) a
LEFT JOIN ( SELECT CHANNEL_CODE, CHANNEL_NAME AS channelName FROM tb_channel_info WHERE DEL_FLAG = 0 ) b ON a.channelNo = b.CHANNEL_CODE
) a
LEFT JOIN ( SELECT AGGTEGATE_REQUEST_CODE, TIME_END AS payTime FROM tb_wxpay_order_business WHERE DEL_FLAG = 0 AND IS_VALID = 0 ) b ON a.aggtegateRequestCode = b.AGGTEGATE_REQUEST_CODE
WHERE
1 = 1

[lovecy]

```
啊哈哈哈哈，没有效果啊，白格式化了大半天，貌似 markdown 语法也无效
```

[shakoon]

说实话我没看懂这个拉屎人的目的，left join 一堆东西但最后都没有用到 join 得到的字段。

SELECT AA.PLATFORM_REQUEST_CODE AS PLATFORMREQUESTCODE,
AA.AGGTEGATE_REQUEST_CODE AS AGGTEGATEREQUESTCODE,
AA.CREATE_TIME AS CREATETIME,
AA.STATUS AS PAYSTATUS,
AA.MERCHANT_GENERATE_CODE AS PLATFORMCODE,
AA.USER_CODE AS BUYCODE,
AA.CHANNEL_NO AS CHANNELNO
FROM TB_AGGTEGATE_PAYMENT_REQUEST AA
LEFT JOIN TB_CHANNEL_SEND_REPORT BB
ON BB.DEL_FLAG = 0
AND AA.AGGTEGATE_REQUEST_CODE = BB.CHANNELAGGTEGATEREQUESTCODE
LEFT JOIN TB_MERCHANT_INFO CC
ON CC.DEL_FLAG = 0
AND CC.MERCHANT_INFO_CODE = AA.MERCHANT_GENERATE_CODE
LEFT JOIN TB_USER_INFO DD
ON DD.DEL_FLAG = 0
AND AA.USER_CODE = DD.PLATFORM_USER_CODE
LEFT JOIN TB_CHANNEL_INFO EE
ON EE.DEL_FLAG = 0
AND AA.CHANNEL_NO = EE.CHANNEL_CODE
LEFT JOIN TB_WXPAY_ORDER_BUSINESS FF
ON FF.DEL_FLAG = 0
AND FF.IS_VALID = 0
AND AA.AGGTEGATE_REQUEST_CODE = FF.AGGTEGATE_REQUEST_CODE
WHERE AA.STATUS != '00'
AND AA.DEL_FLAG = 0
AND AA.IS_VALID = 0
ORDER BY AA.CREATE_TIME DESC

[shakoon]

@xxlee #32 @xxlee #37 没错，我整理了一下，发现这坨屎的核心也就中间那十行
@luxinfl #42 查不查到 name 有什么关系呢，最后的结果集并没有 name，所有的 join 都没有用处，反而可能会导致结果集数量上有增加，里面若干重复的数据

[realpg]

以前在一个公司招聘 PHP，有一个 JAVA 开发商业软件转过来的大佬。

面试题有一个数据库结构跟所要的查询结果格式比较蹩脚的题，基本考察就是性能考虑，这么进行交叉，循环设计

这个大佬拿笔记本摆弄了半天，非常牛逼的特意给我炫耀他接这题的方式，一条 2KB 的 SQL 语句拼接……

那还是跑在笔记本的测试库下本身也就几十万数据量下，一个查询卡了能有 0.5 秒……

[pydiff]

是我的话我直接扔回给写的人,看着就觉得恶心