sql - Get all entries from one table together with the count of these entries in another table -

-

I have 3 tables:

  • The user (id, name, ... < / Li>
  • Item (id, name, ...)
  • download (user_id, item_id, ...)

How do I get all the users With the number of downloads they have?

How do I get all the users together With the number of downloads?

Use: 

  SELECT u.name, COUNT (d.user_id) users 'num_downloaded' and download the OIN S on d.user_id = u.user_id GROUP by u.name

If you want to see how many times a user has downloaded a particular item:

Select username 'user_name', name 'item_name', COUNT (DUGEER_ID), and download the user from 'UN downloads'. D.user_id = u.user_id iitit_id = d on iits Add the .item_id group to U.Name, i.name

Comments

Post a Comment

Popular posts from this blog

Is there an open source WebSockets (JavaScript) XMPP library? -

-
Has anyone written the open source XMPP library that uses the websacet and is being run by a browser? We do not yet have a standard XMPP that can enforce the server, Must be adequately faced before it may be necessary The first step is to eliminate WebSAT standardization. It seems that it can be in an IETF Haib working group, which has not been approved by the IESG so far in the writing time (see) a few weeks ago (Hiroshima), a hybrid bird-of-a-feather in IETF ( BOF), which went very well. WebSketches have a constant reference, and it seems to be systematically organized, one will make XMPP binding for webmasters, possibly with a bar for every webset frame. Edit: Jack Moffitt has written an IETF can be used with the first pass on a protocol. Warning . It is still likely to change fast enough, only apply it if you are ready to wrap it completely later. Warning
Read more

java - Is there an object like a "Set" that can contain only unique string values, but also contain a count on the number of occurrences of the string value? -

-
There is an object like "set" in Java that can contain only unique string values, but it also includes a count Is the number of string value in number? This idea is simple. A data set, ALA ... ABBCCC I will set the text of each line set- I want to add to the object every time a non-unique text is added to the set, I also want to show a numeric value associated with the set to show how often it was added. So if I run it on the above data then set output will be something like this: A: 1B: 2C: 3 Any ideas? Maps & lt; String, integer & gt; add public null (strings) {if (map.containsKey (s)) {map.put (s, map.get (s) + 1); } And {map.put (S, 1); }}
Read more

iphone - How do I make a UIPickerView in a UIActionSheet -

-
Just want to know how I will create UIPickerView in a UIActionSheet with a simple array. Well, I really know how to put it in an action sheet but I like my way because it is more for my app, thanks, but I I also want to know how to put options in UIPKviewView, I just have an array with colors already on top of that part: red, green, blue, yellow, black, etc. in this, but I want to know how it In the preview d L'be if I am using the already Instifrem:? Please help anyone. I know that this is a stupid question, but I'm cheating my head on my $$$$$$ MacBook. Instead you want to do this, create your UIPickerView interface builder and have it in your view controller Connect to the outlet. Add it as a subview of your main view and set its frame coordinates so that it is offset right below the edge, x = 0, y = 480 Then, when you want to display a picker, animate it like something with the screen: [UIView startup permissions: zero reference: zero]; [Color picture setfr...
Read more