我有一个包含评论和答复的表。我正在使用以下查询来获取父母身份，然后从那里获取应该与父母身份相关的答复。
我面临的问题是，当我获取数据时，可以按列（回复）组织数据，但不能按时间戳组织数据。或者似乎postgresql完全忽略了第二个顺序。
parentid | replyid | commentowner | username | commentbody | postcreation
------------------+------------------+---------------+----------+-------------------------------------------------------------------------------------------------------+----------------------------
gLKysUwsL5CVHRIR | 3X77KW5t9X43Psfp | bob@none.com | Bobert | Some Lame Comment.... | 2018-05-08 13:21:43.049563
yt1SLuFzRz1Nlri2 | BG7mm4cj7Q3Ujffs | bob@none.com | Bobert | another parent comment | 2018-05-08 13:22:05.677257
| 3X77KW5t9X43Psfp | bob@none.com | Bobert | latest reply | 2018-05-08 13:22:37.535039
| 3X77KW5t9X43Psfp | bob@none.com | Bobert | no I am the latest | 2018-05-08 13:22:52.868424
| BG7mm4cj7Q3Ujffs | bob@none.com | Bobert | I am a response to to another parent | 2018-05-08 13:23:42.167327
| 3X77KW5t9X43Psfp | mike@none.com | Mikey | I am a response to to another parent | 2018-05-09 08:27:22.733211
| 3X77KW5t9X43Psfp | mike@none.com | Mikey | Mike sent this!! | 2018-05-09 08:27:50.1
和用户表：
username | socialkey | emailaddress | bannerpic | avatarpic
----------+------------------------------------------------------------------+---------------+------------------------------------------------------------------------------+------------------------------------------------------------------------------------
Bobert | 9784e946c53d44c975ee91625486d758fe630f176d44863080ec689ae3cd536a | bob@none.com | https://craftedin.co/static/images/user/headers/59d9bce7c33561.24964635.jpg | https://craftedin.co/static/images/user/avatars/thumbs/59159be40a8c76.26091804.jpg
Mikey | 3bcd6c5f811ba06aa49c2df9504fe5416f35702b78bcdc15ecbd5137fabdca59 | mike@none.com | https://i.pinimg.com/originals/29/85/16/298516524d3ed9eb35ea9aae0f111ab3.jpg | https://images.pexels.com/photos/617278/pexels-photo-617278.jpeg
如果这有助于制作某种Codepen或其他东西，请告诉我，我会尽力做到这一点。
这是我正在运行的查询：
with parents as (select distinct replyid from comments where commentowner = (select emailaddress from users where SocialKey = ('9784e946c53d44c975ee91625486d758fe630f176d44863080ec689ae3cd536a')) and parentid IS NOT NULL LIMIT 5 ), socialkeys as (select distinct socialkey,emailaddress,avatarpic from users) select distinct comments.parentid, comments.replyid,comments.username, comments.commentbody,comments.postcreation from comments left join parents on parents.replyid = comments.replyid left join socialkeys on comments.commentowner = socialkeys.emailaddress where parents.replyid = comments.replyid order by replyid, postcreation;
这是我收到的数据：
parentid | replyid | username | commentbody | postcreation
------------------+------------------+----------+-------------------------------------------------------------------------------------+----------------------------
gLKysUwsL5CVHRIR | 3X77KW5t9X43Psfp | Bobert | Some Lame Comment.... | 2018-05-08 13:21:43.049563
| 3X77KW5t9X43Psfp | Bobert | latest reply | 2018-05-08 13:22:37.535039
| 3X77KW5t9X43Psfp | Bobert | no I am the latest | 2018-05-08 13:22:52.868424
| 3X77KW5t9X43Psfp | Mikey | I am a response to to another parent | 2018-05-09 08:27:22.733211
| 3X77KW5t9X43Psfp | Mikey | Mike sent this!! | 2018-05-09 08:27:50.140229
| 3X77KW5t9X43Psfp | Bobert | bob | 2018-06-28 14:22:07.131133
| 3X77KW5t9X43Psfp | Bobert | Oh so this really does work? | 2018-06-28 14:27:02.956613
| 3X77KW5t9X43Psfp | Bobert | this is a reply | 2018-06-28 17:41:49.071165
wpdcBFUft0r597IK | 4WMFSMSTSomjdoD9 | Bobert | this is parent comment number 5 I think the database is set to limit 5... | 2018-06-28 18:15:47.534429
yt1SLuFzRz1Nlri2 | BG7mm4cj7Q3Ujffs | Bobert | another parent comment | 2018-05-08 13:22:05.677257
| BG7mm4cj7Q3Ujffs | Bobert | I am a response to to another parent | 2018-05-08 13:23:42.167327
| BG7mm4cj7Q3Ujffs | Bobert | Another lame coment reply | 2018-05-19 12:55:56.090902
pw22kSb7MdA9Nx5G | MD3jA9znknV9c3p7 | Bobert | This is a new comment from bobbert on the new interfce | 2018-06-28 18:03:30.05851
bffV59nEQRg5YtP3 | tIZYNjkyzoHhKfza | Bobert | This is comment # 6... This should show up becasue it is the newest! of the newsts! | 2018-06-28 18:16:12.823547
这是我想收到的。所有评论都已按replyid收集并排序，但是我希望这些评论也与他们的输入时间保持一致。我希望这是有道理的。我已经尝试了所有内容。
parentid | replyid | username | commentbody | postcreation
------------------+------------------+----------+-------------------------------------------------------------------------------------+----------------------------
gLKysUwsL5CVHRIR | 3X77KW5t9X43Psfp | Bobert | Some Lame Comment.... | 2018-05-08 13:21:43.049563
| 3X77KW5t9X43Psfp | Bobert | latest reply | 2018-05-08 13:22:37.535039
| 3X77KW5t9X43Psfp | Bobert | no I am the latest | 2018-05-08 13:22:52.868424
| 3X77KW5t9X43Psfp | Mikey | I am a response to to another parent | 2018-05-09 08:27:22.733211
| 3X77KW5t9X43Psfp | Mikey | Mike sent this!! | 2018-05-09 08:27:50.140229
| 3X77KW5t9X43Psfp | Bobert | bob | 2018-06-28 14:22:07.131133
| 3X77KW5t9X43Psfp | Bobert | Oh so this really does work? | 2018-06-28 14:27:02.956613
| 3X77KW5t9X43Psfp | Bobert | this is a reply | 2018-06-28 17:41:49.071165
yt1SLuFzRz1Nlri2 | BG7mm4cj7Q3Ujffs | Bobert | another parent comment | 2018-05-08 13:22:05.677257
| BG7mm4cj7Q3Ujffs | Bobert | I am a response to to another parent | 2018-05-08 13:23:42.167327
| BG7mm4cj7Q3Ujffs | Bobert | Another lame coment reply | 2018-05-19 12:55:56.090902
pw22kSb7MdA9Nx5G | MD3jA9znknV9c3p7 | Bobert | This is a new comment from bobbert on the new interfce | 2018-06-28 18:03:30.05851
wpdcBFUft0r597IK | 4WMFSMSTSomjdoD9 | Bobert | this is parent comment number 5 I think the database is set to limit 5... | 2018-06-28 18:15:47.534429
bffV59nEQRg5YtP3 | tIZYNjkyzoHhKfza | Bobert | This is comment # 6... This should show up becasue it is the newest! of the newsts! | 2018-06-28 18:16:12.823547
我这样做完全错误吗？还是我缺少一些简单的东西？
请让我知道，谢谢。
答案 0 :(得分：1)
根据您的发现，从2个输出中看来，具有parentid = wpdcBFUft0r597IK的条目的顺序错误。只有一个条目带有该父ID，因此您的查询不在乎父ID的显示顺序。如果您希望按父ID的后置排序，请尝试将查询更改为以下内容。
with parents
as (select replyid,
min(postcreation) postcreation
from comments
where commentowner = (select emailaddress
from users
where socialkey = ('9784e946c53d44c975ee91625486d758fe630f176d44863080ec689ae3cd536a'))
and parentid is not null
group by replyid limit 5),
socialkeys
as (select distinct socialkey,
emailaddress,
avatarpic
from users)
select distinct parents.postcreation,
comments.parentid,
comments.replyid,
comments.username,
comments.commentbody,
comments.postcreation
from comments
left join parents on parents.replyid = comments.replyid
left join socialkeys on comments.commentowner = socialkeys.emailaddress
where parents.replyid = comments.replyid
order by parents.postcreation,
comments.replyid,
comments.postcreation;
我将您的父母CTE更改为分组依据，以便您可以在订购依据中使用MIN POSTCREATION。我还用表名限定了ORDER BY字段，以防在REPLYID排序时出现歧义。
-HTH