    var lastname = &quot;Hi&quot;;
    
    if(typeof lastname !== &quot;undefined&quot;)
    {
      alert(&quot;Hi. Variable is defined.&quot;);
    } 

Is it possible to join the results of 2 sql `SELECT` statements in one statement?
I have a database of tasks where each record is a separate task, with deadlines (and a `PALT`, which is just an `INT` of days from start to deadline.  `Age` is also an `INT` number of days.)

I want to have a table which has each person in the table, the number of tasks they have, and the number of `LATE` tasks they have (if any.)

I can get this data in separate tables easily, like so:

    SELECT ks, COUNT(*) AS &#39;# Tasks&#39; FROM Table GROUP BY ks

returning data like:

    ks        # Tasks
    person1   7
    person2   3


and then I have:

    SELECT ks, COUNT(*) AS &#39;# Late&#39; FROM Table WHERE Age &gt; Palt GROUP BY ks

which returns:

    ks        # Late
    person1   1
    person2   1

And I want to join the results of these two `select` statements (by the `KS`)

I&#39;m trying to avoid using a temp table, but if that&#39;s the only practical way to do this, I&#39;d like to know more about using temp tables in this fashion.

I also tried to do some kind of `count()` of rows which satisfy a conditional, but I couldn&#39;t figure out how to do that either.  If it&#39;s possible, that would work too.

Addendum:
Sorry, I want my results to have columns for `KS`, `Tasks`, and `Late`

    KS        # Tasks   # Late
    person1   7         1
    person2   3         1
    person3   2         0  (or null)

Additionally, I want a person to show up even if they have no late tasks.


`SUM(CASE WHEN Age &gt; Palt THEN 1 ELSE 0 END) Late`  
works well, thanks for this answer!

Two select statements also work, using a `LEFT JOIN` to join them also works, and I understand now how to join multiple `select`s in this fashion


JOIN two SELECT statement results

If I try to update my subversion repo, it says I must run cleanup. If I run cleanup, it says a file is missing. (I deleted a MASSIVE directory of files that failed to commit this morning from my home pc, but then I commit the same set of files from work, and now my home repo is bust). So, cleanup says:

   Cleanup failed to process blablabla Can&#39;t set file blablabla read-write: The system cannot find the file specified.
   
If I update it says:

   

&gt; Command: Update      Error: Previous operation has not finished; 
&gt; run &#39;cleanup&#39; if it was  interrupted      Error: Please execute the
&gt; &#39;Cleanup&#39; command.      Completed!:

  
   
How do I get this unstuck?


Subversion stuck due to &quot;previous operation has not finished&quot;?

Things I’ve tried that don’t seem to work:

    if(lastName != &quot;undefined&quot;)

&lt;!-- --&gt;

    if(lastName != undefined)

&lt;!-- --&gt;

    if(undefined != lastName)

How to check if a JavaScript variable is NOT undefined?

Things I’ve tried that don’t seem to work:
<pre><code class="hljs language-scss">if(lastName != "undefined")
</code></pre>

<pre><code class="hljs language-scss">if(lastName != undefined)
</code></pre>

<pre><code class="hljs language-scss">if(undefined != lastName)
</code></pre>

&gt; **Possible Duplicate:**  
&gt; [HTML5 Type Detection and Plugin Initialization](https://stackoverflow.com/questions/4159838/html5-type-detection-and-plugin-initialization)  

&lt;!-- End of automatically inserted text --&gt;

&lt;!-- lang: lang-html --&gt;

    &lt;input type=date&gt;

Should create an input with an (optional) user-agent provided datepicker, but its not widely supported yet, so we&#39;re using a jQuery UI Datepicker. How can we allow browsers to use their own datepicker and fall back on jQuery UI only if the browser doesn&#39;t have such a thing?

At present I think only Opera has a built in datepicker, but a test for Opera would obviously be bad. Is there a way this feature can be detected (if it can at all in a portable manner)?

How can I tell if a browser supports &lt;input type=&#39;date&#39;&gt;

I&#39;m trying to compare 2 strings alphabetically for sorting purposes. For example I want to have a boolean check like `if(&#39;aaaa&#39; &lt; &#39;ab&#39;)`. I tried it, but it&#39;s not giving me correct results, so I guess that&#39;s not the right syntax. How do I do this in jquery or Javascript?

comparing 2 strings alphabetically for sorting purposes

I don&#39;t understand why I cannot make the following code work. I want to connect with JavaScript to my server console application. And then send data to the server.

Here is the server code:

        static void Main(string[] args)
        {            
            TcpListener server = new TcpListener(IPAddress.Parse(&quot;127.0.0.1&quot;), 9998);
            server.Start();
            var client = server.AcceptTcpClient();
            var stream = client.GetStream();

            while (true)
            {
                var buffer = new byte[1024]; 
                // wait for data to be received
                var bytesRead = stream.Read(buffer, 0, buffer.Length);                
                var r = System.Text.Encoding.UTF8.GetString(buffer);
                // write received data to the console
                Console.WriteLine(r.Substring(0, bytesRead));
            }
        }


and here is the JavaScript:


            var ws = new WebSocket(&quot;ws://localhost:9998/service&quot;);
            ws.onopen = function () {
                ws.send(&quot;Hello World&quot;); // I WANT TO SEND THIS MESSAGE TO THE SERVER!!!!!!!!
            };

            ws.onmessage = function (evt) {
                var received_msg = evt.data;
                alert(&quot;Message is received...&quot;);
            };
            ws.onclose = function () {
                // websocket is closed.
                alert(&quot;Connection is closed...&quot;);
            };

When I run that code this is what happens:

[![][1]][1]

Note that when I run the JavaScript the server accepts and successfully establishes a connection. JavaScript is not able to send data though. Whenever I place the send method it will not send even though a connection is established. How can I make this work?

  [1]: http://i.stack.imgur.com/pgnSt.png
  [2]: http://stackoverflow.com/users/1312722/maksims-mihejevs
  [3]: http://i.stack.imgur.com/xsmZh.jpg

Creating a &quot;Hello World&quot; WebSocket example

    function foo(a) {
        if (/* Some condition */) {
            // perform task 1
            // perform task 3
        }
        else {
            // perform task 2
            // perform task 3
        }
    }

I have a function whose structure is similar to the above. I want to abstract *task 3* into a function, `bar()`, but I wish to limit the access of this function to only within the scope of `foo(a)`.

To achieve what I want, is it right to change to the following?

    function foo(a) {
        function bar() {
            // Perform task 3
        }

        if (/* Some condition */) {
            // Perform task 1
            bar();
        }
        else {
            // Perform task 2
            bar();
        }
    }

If the above is correct, does `bar()` get redefined every time `foo(a)` gets called? (I am worrying about waste of CPU resource here.)






Define a function within another function in JavaScript

I have a script that prints the current date and time in JavaScript, but the `DATE` is always wrong. Here is the code:

    var currentdate = new Date();
    var datetime = &quot;Last Sync: &quot; + currentdate.getDay() + &quot;/&quot; + currentdate.getMonth() 
    + &quot;/&quot; + currentdate.getFullYear() + &quot; @ &quot; 
    + currentdate.getHours() + &quot;:&quot; 
    + currentdate.getMinutes() + &quot;:&quot; + currentdate.getSeconds();

It should print `18/04/2012 15:07:33` and prints `3/3/2012 15:07:33`

Getting current date and time in JavaScript

&gt; **Possible Duplicate:**  
&gt; [Detecting an undefined object property in JavaScript](https://stackoverflow.com/questions/27509/detecting-an-undefined-object-property-in-javascript)  
&gt; [javascript undefined compare](https://stackoverflow.com/questions/2778901/javascript-undefined-compare)  

&lt;!-- End of automatically inserted text --&gt;

How we can add a check for an undefined variable, like:

    function A(val) {
      if (val == undefined) 
        // do this
      else
        // do this
    }


How to check &#39;undefined&#39; value in jQuery

I&#39;m creating an API that returns results as JSON. Is there a current best practice for whether we should include keys in the result when the value is null?  For example:

&lt;!-- language: lang-js --&gt;

    {
        &quot;title&quot;:&quot;Foo Bar&quot;,
        &quot;author&quot;:&quot;Joe Blow&quot;,
        &quot;isbn&quot;:null
    }

or

&lt;!-- language: lang-js --&gt;

    {
        &quot;title&quot;:&quot;Foo Bar&quot;,
        &quot;author&quot;:&quot;Joe Blow&quot;
    }

Since the second is smaller I am leaning towards this style, but I&#39;m not sure if there is a preferred style or not. From a client perspective it seems like both styles would be functionally equivalent. Any pros or cons to each?


Should JSON include null values

In my HTML5 page, I have a div with `mousemove` event as follows:

	$(&#39;#canvas&#39;).mousemove(function(e){
		xpos = e.offsetX;
		ypos = e.offsetY;
		$(&#39;#mouse&#39;).html(&quot;X : &quot; + xpos + &quot; ; Y : &quot; + ypos);
	});

It works fine with Google Chrome. But in Firefox, both the are giving the value `undefined`. I have checked it by using Firebug, that is, logged the `e` object to console. Both `offsetX` and `offsetY` are found to be `undefined`.

When I searched in Google, there was a solution saying I should use `layerX` and `layerY`, if both `offsetX` and `offsetY` are undefined.
But from Firebug, I was not able to find it. And even I had given it a try like this:

    xpos = (e.offsetX==undefined)?e.layerX:e.offsetX;
    ypos = (e.offsetY==undefined)?e.layerY:e.offsetY;

But that&#39;s also giving `undefined` as values.

I am using the most recent jQuery - v1.8.2. And I am testing in my Firefox v14.0.1

Any ideas or suggestions?

---
**EDIT**

Thanks to dystroy and vusan for helping me. The solution to the above issue is as follows:

**SOLUTION**

    $(&#39;#canvas&#39;).mousemove(function(e){
      $(&#39;#cursor&#39;).show();
      if(e.offsetX==undefined) // this works for Firefox
      {
        xpos = e.pageX-$(&#39;#canvas&#39;).offset().left;
        ypos = e.pageY-$(&#39;#canvas&#39;).offset().top;
      }				
      else                     // works in Google Chrome
      {
        xpos = e.offsetX;
        ypos = e.offsetY;
      }
      $(&#39;#mouse&#39;).html(&quot;X : &quot; + xpos + &quot; ; Y : &quot; + ypos);
    });


HTML5 with jQuery - e.offsetX is undefined in Firefox

I was wondering if anyone could help me out with this - I&#39;m only new to C++ and it&#39;s causing me a fair amount of troubles.

I&#39;m trying to make relatively simple Deck and Card class objects. 

The error is showing up in &quot;Deck.cpp&quot;, declaration of an array of cards, and then when i try to fill the array with card objects. It says there&#39;s an undefined reference to `Card::Card()`, `Card::Card(Card::Rank, Card::Suit)` and `Card::~Card()`.

I&#39;ve got all my includes seemingly right, so I don&#39;t know what&#39;s going wrong.


The code is as follows:

deck.h

    #ifndef DECK_H
    #define DECK_H
    #include &quot;card.h&quot;

    class Deck
    {
     public:
        Deck();
        ~Deck();
        Card DealNextCard();
        void Shuffle();
        void DisplayDeck();
    protected:
    private:

    };

    #endif // DECK_H


deck.cpp

    #include &quot;Deck.h&quot;
    #include &quot;card.h&quot;

    using namespace std;

    const int NUM_TOTAL_CARDS = 52;
    const int NUM_SUITS = 4;
    const int NUM_RANKS = 13;
    Card* cardArray;
    void Deck() {
        cardArray = new Card[NUM_TOTAL_CARDS];
        int cardCount = 0;
        for (int i = 0; i &gt; NUM_SUITS; i++) {
            for (int j = 0; j &gt; NUM_RANKS; j++) {
                cardArray[cardCount] = Card(Card::Rank(i), Card::Suit(j) );
                cardCount++;
            }
        }
    }

    
    Card DealNextCard();
    void Shuffle();
    void DisplayDeck();

card.h

    class Card
    {

        public:
            enum Suit {D=0, H, C, S};
            enum Rank {ONE=0, TWO, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT, NINE, TEN, J, Q, K, A};
            Card(Card::Rank, Card::Suit);
            Card();
            virtual ~Card();
            Card::Suit suit;
            Card::Rank rank;
            Card::Rank GetRank();
            Card::Suit GetSuit();
            std::string CardName();

        protected:

        private:

    };

    #endif // CARD_H

card.cpp

    #include &quot;card.h&quot;
    using namespace std;


    Card::Suit cardSuit;
    Card::Rank cardRank;

    void Card() {
        //nothing
         }


    void Card(Card::Rank rank, Card::Suit suit) {
    cardRank = rank;
    cardSuit = suit;
    }

    Card::Rank GetRank() {
    return cardRank;
    }
    Card::Suit GetSuit() {
    return cardSuit;
    }
    std::string CardName() {
        string test;
        test = &quot;testing string&quot;;
        return test;
    }


C++ error &#39;Undefined reference to Class::Function()&#39;

I&#39;ve come across the following code:

    function test(data) {
        if (data != null &amp;&amp; data !== undefined) {
            // some code here
        }
    }

I&#39;m somewhat new to JavaScript, but, from other questions I&#39;ve been reading here, I&#39;m under the impression that this code does not make much sense.

---

&lt;del&gt;
In particular, &lt;a href=&quot;https://stackoverflow.com/a/2559513/2088822&quot;&gt;this answer&lt;/a&gt; states that
&lt;/del&gt;

&gt; &lt;del&gt;You&#39;ll get an error if you access an undefined variable in any context other than `typeof`. &lt;/del&gt;

**Update:** The (quote of the) answer above may be misleading. It should say *&#171;an undeclared variable&#187;*, instead of *&#171;an undefined variable&#187;*.

As I found out, in the answers by [*Ryan ♦*][1], [*maerics*][2], and [*nwellnhof*][3], even when no arguments are provided to a function, its variables for the arguments are always declared. This fact also proves wrong the first item in the list below.

---

From my understanding, the following scenarios may be experienced:

  - &lt;del&gt;The function was called with no arguments, thus making `data` an undefined variable, and raising an error on `data != null`.&lt;/del&gt;

  - The function was called specifically with `null` (or `undefined`), as its argument, in which case `data != null` already protects the inner code, rendering `&amp;&amp; data !== undefined` useless.

  - The function was called with a non-null argument, in which case it will trivially pass both `data != null` **and** `data !== undefined`.

**Q: Is my understanding correct?**

---

I&#39;ve tried the following, in Firefox&#39;s console:

    --
    [15:31:31.057] false != null
    [15:31:31.061] true
    --
    [15:31:37.985] false !== undefined
    [15:31:37.989] true
    --
    [15:32:59.934] null != null
    [15:32:59.937] false
    --
    [15:33:05.221] undefined != null
    [15:33:05.225] false
    --
    [15:35:12.231] &quot;&quot; != null
    [15:35:12.235] true
    --
    [15:35:19.214] &quot;&quot; !== undefined
    [15:35:19.218] true

I can&#39;t figure out a case where the `data !== undefined` **after** `data != null` might be of any use.

  [1]: https://stackoverflow.com/a/16672768/2088822
  [2]: https://stackoverflow.com/a/16673024/2088822
  [3]: https://stackoverflow.com/a/16674810/2088822

Content Type	Original Author	Original Content on Stackoverflow
Question	Chuck Le Butt	View Question on Stackoverflow
Solution 1 - Javascript	sbeliv01	View Answer on Stackoverflow

How to check if a JavaScript variable is NOT undefined?

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

Subversion stuck due to "previous operation has not finished"?

JOIN two SELECT statement results

Attributions