StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
primarykey
Id
20831698
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
CommentCount
0
CommunityOwnedDate
CreationDate
2013-12-30T00:25:02.250
FavoriteCount
0
LastActivityDate
2013-12-30T00:52:26.793
LastEditDate
2013-12-30T00:52:26.793
LastEditorUserId
1481489
OwnerUserId
1481489
ParentId
20831524
PostTypeId
2
Score
1
ViewCount
0
LastEditorDisplayName
text
Body
Edit: meh, missed the detail about selecting the username, not constraining by the username. Here is the correct answer: <pre><code>SELECT * FROM `users_categories` AS `uc` INNER JOIN `users` AS `u` ON `u`.`ID`=`uc`.`userid` WHERE `uc`.`categoryid` IN (1,2) GROUP BY `uc`.`userid` HAVING COUNT(`uc`.`userid`) >= 2 </code></pre> Fiddle: <a href="http://sqlfiddle.com/#!2/8fdca/9" rel="nofollow">http://sqlfiddle.com/#!2/8fdca/9</a> Leaving the original answer for historical purposes. <hr> Yes, this is possible with table joins. The constraints are <code>username</code> and <code>categoryid</code> ...for john: <pre><code>SELECT `c`.* FROM `users` AS `u` INNER JOIN `users_categories` AS `uc` ON `uc`.`userid`=`u`.`ID` AND `uc`.`categoryid` IN (1,2) INNER JOIN `categories` AS `c` ON `c`.`ID`=`uc`.`categoryid` WHERE `u`.`username`='john'; </code></pre> Fiddle: <a href="http://sqlfiddle.com/#!2/8fdca/1" rel="nofollow">http://sqlfiddle.com/#!2/8fdca/1</a> <hr> The query will also work if you remove the <code>categoryid</code> constraint (to get all categories for a given username) by removing <code>AND uc.categoryid IN (1,2)</code> ...for billy this time: <pre><code>SELECT `c`.* FROM `users` AS `u` INNER JOIN `users_categories` AS `uc` ON `uc`.`userid`=`u`.`ID` INNER JOIN `categories` AS `c` ON `c`.`ID`=`uc`.`categoryid` WHERE `u`.`username`='billy'; </code></pre> Fiddle: <a href="http://sqlfiddle.com/#!2/8fdca/3" rel="nofollow">http://sqlfiddle.com/#!2/8fdca/3</a> <hr> Furthermore, if you already know the user's ID, this can be simplified even further ...for bob (id #2) now: <pre><code>SELECT `c`.* FROM `users_categories` AS `uc` INNER JOIN `categories` AS `c` ON `c`.`ID`=`uc`.`categoryid` WHERE `uc`.`userid`=2; </code></pre> Fiddle: <a href="http://sqlfiddle.com/#!2/8fdca/5" rel="nofollow">http://sqlfiddle.com/#!2/8fdca/5</a>
Tags
Title
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. POSelect from mapping table
 singulars
 PostTypePostTypeId
 PTQuestion
PostTypePostTypeId
1. PTAnswer
UserLastEditorUserId
1. USzamnuts
UserOwnerUserId
1. USzamnuts
plurals
PostLinksPostIdRelatedPostId
1. This table or related slice is empty.
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. This table or related slice is empty.
CommentsPostId
1. This table or related slice is empty.

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.