Learning SQL development can seem like an overwhelming task at first. However, mastering just a few key points will help ease your way through 80 percent of the day-to-day challenges when writing stored procedures and solving common problems. Here are three important SQL development factors to keep in mind:

Outer Joins
One of the most crucial things to understand in SQL server are joins. Joins are a way to retrieve data from two or more tables based on logical relationships between them. Joins dictate how Microsoft SQL Server ought to use data from one table to select the rows in another table.

In my experience inner joins are intuitive while outer joins can present additional hours of grief by overlooking associations in the other table(s). The outer join is the key to answering questions about what the database does not have. For example, if you need to make a query to display all the students who are without report-cards, you’ll need a left join to get all students coupled with a “where clause” to return the ones who have nulls for their report card table columns in the results.

Many talented Java script programmers have muddled through the SQL Server by deficient coding around the inner join. As a result, their queries can take five hours to run, whereas, properly written left joins, can take only two seconds to run.

Aggregation
Grouping results comes up in SQL a lot more than you might think. Knowing how to write a query when answering questions such as, “What’s the average grade for each teacher’s student list?” is invaluable. This kind of question cannot be answered with a single table or solely by joins.  You’ll often find you need to use joins in conjunction with group by statements. Always write the raw query first and then look at the results. Next, you have to figure out the best way to group them, rewrite your select clause and add a group by clause in the end.

Digging Through Data
I find this is the most lacking skill in many programmers. In fact, many otherwise-talented programmers holding Master’s Degrees fail to get jobs because they couldn’t analyze rows of data objectively during interviews. It’s just something that’s not taught but is crucial to get under you belt. Why? Eventually, some query is not going to perform as you may expect. And, the only way to find discrepancies is to look at rows of data, identify what join isn’t finding a match or where bad data is throwing things into chaos. Get familiar with how joins actually work, even if you have to manually walk through the logic of a large stored procedure’s tree of joins. It’s boring and time-consuming but absolutely necessary.

Take the time to master the core skills that will make you a successful SQL Programmer and avoid queries that run for five hours!

Static variables in Python are created as part of the class declaration.  By contrast, instance variables are created as part of a regular method and not a classmethod or staticmethod.

class A:
  i=3  # static variable
	
  def dosomethingregularmethod(self):
       self.k=4   # instance variable
	
# to access static variables


A.i

Have you ever played a game on your iPhone and wondered how to share it with your friends? Of course, not everyone has iPhones, and they aren’t always watching the leaderboards on the Gaming app, provided by Apple. Well, guess what? You don’t have to take a whole other camera to take a picture of your iPhone to create a photo of that particular score you have achieved. All you have to do is simultaneously press the “Home Button” and the “Lock Button” on your iPhone. After that, your iPhone should consequently flash to white, as if it were snapping its shutter, and taking a picture. Afterwards, you should be able to find the picture in your Photo Albums and share it with your friends.                                                                                        

But, taking screenshots of your iPhone doesn’t always have to deal with your game scores, you can take screenshots of almost any happening on your phone and share it with people! Have you ever had a memorable texting conversation with your friend, where you mistyped something, and the conversation went haywire? Sharing it becomes easy by using this feature. Want to show how odd a website looks on your iPhone compared to looking at it on your computer, and give it to their support to fix it? Take a screenshot of it! The possibilities of this feature are endless, and can become timeless with a simple picture.

Javascript has a lot of features which are often overlooked by web developers, and one such feature is the ability to have timed events. If you do not understand what that means do not worry because all will be explained in this tutorial.

Timing events allow you to write code which will execute within a set amount of time. As an example, say you wanted to display a clock on your web page. You could use javascripts' built in timing functions to make the time change every second or every minute.

Of course there are other uses for such functions, but we will stick with a simple timer which creates a dialog box with the words Hi There on it every 3 seconds, that way you can get a feel for how to work with timing.

To get started we are going to need a basic web page. Just create a blank page and add the following code in the script tags: