mysql - SQL Limit & Order By across joins -


I am accumulating tweets, twitter user and categorizing twitter user in groups.

I have the following 4 tables

Tweets: 

  tweet_id | User_id | Created --------------------------- 23452345 | 2345 | 2013-08-12 23456094 | 1234 | 2014-03-24 230 9 7777 | 1234 | 2014-04-12 23 948798 | 99 99 | 2013-09-22   
 twitter_users:  
  user_id | Screen_name ------------------------ 2345 | Michael 1234 | David 99 99 | Not_interested   
 twitter_social:  
  user_id | Social_id ------------------------- 2345 | 34 99 99 | 20 1234 | 80   
 Social Tags:  
  social_id | Category_ID ----------------------- 34 | 3 20 6 80 3   
 I want to see the oldest tweet per user that appears in a specific social category. The written SQL I wrote does not seem to work. I have a line per  twitter_user  but I do not see the tweet as soon as possible  
  select tu.screen_name as handle, in the form of tw.created_at In the first twitter_users tu LEFT JOIN tweets on twitter.tu.user_id = tw.user_id LEFT JOIN twitter_social ts ON ts.user_id = tu.user_id LEFT JOIN social_categories CS ON ts.social_id = cs.social_id WHERE cs.category_id = 3 group By order   
  edit  by the oldest ASC I have to have the result as follows  
  handle | Oldest --------------------- David | 2014-03-24 Michael | 2013-08-12    
 
 
  SELECT tu.screen_name In the form of handles, Leave twitter_users tu as MIN (Tw.created_at) first tu.user_id = tw.user_id Join tweets twitter_social ts Leave ts.user_id = tu.user_id on social relations cs tssocial_id = cs.social_id where Cs.category_id = 3 group by the tu.screen_name command, the oldest ASC

Comments

Post a Comment

Popular posts from this blog

Java - Error: no suitable method found for add(int, java.lang.String) -

I'm in the middle of homework work and I'm stuck. At this point in my code, I think that I should have a GUI window that opens and allows me to type "inserted text number". Notice is not going anywhere but at this point, If I pass through the problem then it will be in a linked list. I am getting two of the same error for the lines. Add (index, element); And I can not seem to get past it, there is no suitable method for the error "add (int, java. string string)". Code is below, please advise. To clarify - this will not be a method error because it is a linked list. There should not be any way involved. import java.awt. *; Import java.awt.event. *; Import javax.swing. *; Import java.util. *; Import java.util.Scanner; Import java.util.LinkedList; Public class TopTenList JFrame {Private TopTenList tt; See the Private JTextArea list; Private JTextField cmdTextField; Private JTextField resultsTestfield; // This GUI window is the code for the public toptist...
Read more

java - JPA TypedQuery: Parameter value element did not match expected type -

I am using JPA 2.0 and getting the following code in the DAO layer: Public Zero Test () {string key = "status"; String [] Conditions = {"A", "B"}; & Lt; TestTable & gt; Results = Search (Keys, Conditions); } Public listing & lt; TestTable & gt; Search (string key, object value error) {string sql = "test ndf to testlet and jade nand." + Key + "in:" + key; TypedQuery & LT; TestTable & gt; Query = entityManager.createQuery (SQL, TestTable.class); Query.setParameter (key, Arrays.asList (valueArr)) / *** Error Line *** Return query.getResultList (); } In the above error line, it throws the following exception: java.lang.IllegalArgumentException: parameter value element [[Ljava.lang.String; @ cbe5bc] did not match the expected type [java.lang.String] Why is this expected type string while actually this string []? Please help! Note: This is derived from the normal routine and is a simplified code. I can no...
Read more

c++ - static template member variable has internal linkage but is not defined -

Yes, I know, there is a question with almost the same title, but it refers to a different situation. Error message) In my case, I have a .cpp file with a big named designation name (implementation details). There is a property class template with a static data member in that name space, which I need to access from outside the unknown namespace. I give it a little bit of meat: file.hpp namespace Bar {template & lt; Typename A & gt; Struct foo {static_assert (is_same & lt; a, float & gt; :: value} is_same & lt; a, double>: value, ""); Fixed zero set_static_var (a const & x); // ...}; } and file.cpp namespace {template & lt; Typename A & gt; Struct foo_traits {// supports the implementation of several static code bars: foo & lt; & Gt; Fixed A data; }; The template's & lt; & Gt; Float foo_traits & lt; Float & gt; :: datum; // No change if this is in the global namespace template & lt; & Gt; Doub...
Read more