Technowaves

Google unveiled its Chrome OS operating system during a press event at the company's headquarters, and it's pretty much exactly what was expected it to be: a streamlined Linux kernel booting straight into the Chrome web browser. The code is available starting today.
Download and installation instructions here

INNER JOIN

This join returns rows when there is at least one match in both the tables.

OUTER JOIN

There are three different Outer Join methods.

LEFT OUTER JOIN
This join returns all the rows from the left table in conjunction with the matching rows from the right table. If there are no columns matching in the right table, it returns NULL values.

RIGHT OUTER JOIN
This join returns all the rows from the right table in conjunction with the matching rows from the left table. If there are no columns matching in the left table, it returns NULL values.

FULL OUTER JOIN
This join combines left outer join and right after join. It returns row from either table when the conditions are met and returns null value when there is no match.

CROSS JOIN

This join is a Cartesian join that does not necessitate any condition to join. The resultset contains records that are multiplication of record number from both the tables.

Additional Notes related to JOIN:

The following are three classic examples to display where Outer Join is useful. You will notice several instances where developers write query as given below.

SELECT t1.*
FROM Table1 t1
WHERE t1.ID NOT IN (SELECT t2.ID FROM Table2 t2)
GO

The query demonstrated above can be easily replaced by Outer Join. Indeed, replacing it by Outer Join is the best practice. The query that gives same result as above is displayed here using Outer Join and WHERE clause in join.

/* LEFT JOIN - WHERE NULL */
SELECT t1.*,t2.*
FROM Table1 t1
LEFT JOIN Table2 t2 ON t1.ID = t2.ID
WHERE t2.ID IS NULL

The above example can also be created using Right Outer Join.

NOT INNER JOIN
Remember, the term Not Inner Join does not exist in database terminology. However, when full Outer Join is used along with WHERE condition, as explained in the above two examples, it will give you exclusive result to Inner Join. This join will give all the results that were not present in Inner Join.

An example script of the above all from source

USE AdventureWorks
GO
CREATE TABLE table1
(ID INT, Value VARCHAR(10))
INSERT INTO Table1 (ID, Value)
SELECT 1,'First'
UNION ALL
SELECT 2,'Second'
UNION ALL
SELECT 3,'Third'
UNION ALL
SELECT 4,'Fourth'
UNION ALL
SELECT 5,'Fifth'
GO
CREATE TABLE table2
(ID INT, Value VARCHAR(10))
INSERT INTO Table2 (ID, Value)
SELECT 1,'First'
UNION ALL
SELECT 2,'Second'
UNION ALL
SELECT 3,'Third'
UNION ALL
SELECT 6,'Sixth'
UNION ALL
SELECT 7,'Seventh'
UNION ALL
SELECT 8,'Eighth'
GO
SELECT *
FROM Table1
SELECT *
FROM Table2
GO
USE AdventureWorks
GO
/* INNER JOIN */
SELECT t1.*,t2.*
FROM Table1 t1
INNER JOIN Table2 t2 ON t1.ID = t2.ID
GO
/* LEFT JOIN */
SELECT t1.*,t2.*
FROM Table1 t1
LEFT JOIN Table2 t2 ON t1.ID = t2.ID
GO
/* RIGHT JOIN */
SELECT t1.*,t2.*
FROM Table1 t1
RIGHT JOIN Table2 t2 ON t1.ID = t2.ID
GO
/* OUTER JOIN */
SELECT t1.*,t2.*
FROM Table1 t1
FULL OUTER JOIN Table2 t2 ON t1.ID = t2.ID
GO
/* LEFT JOIN - WHERE NULL */
SELECT t1.*,t2.*
FROM Table1 t1
LEFT JOIN Table2 t2 ON t1.ID = t2.ID
WHERE t2.ID IS NULL
GO
/* RIGHT JOIN - WHERE NULL */
SELECT t1.*,t2.*
FROM Table1 t1
RIGHT JOIN Table2 t2 ON t1.ID = t2.ID
WHERE t1.ID IS NULL
GO
/* OUTER JOIN - WHERE NULL */
SELECT t1.*,t2.*
FROM Table1 t1
FULL OUTER JOIN Table2 t2 ON t1.ID = t2.ID
WHERE t1.ID IS NULL OR t2.ID IS NULL
GO
/* CROSS JOIN */
SELECT t1.*,t2.*
FROM Table1 t1
CROSS JOIN Table2 t2
GO
DROP TABLE table1
DROP TABLE table2
GO

You may have already heard, but the unthinkable has happened. That’s right, Microsoft, the self-proclaimed enemy of Linux and free software, has announced that they will be submitting some 20,000 lines of code to the Linux kernel. Come again? Yes, Microsoft wants to get its code into the Linux kernel. You read that right!

It is important to note that this code has not yet been included into the official Linux kernel. The code has also not yet been thoroughly scrutinized by the wider community to see what the code actually consists of. Is it all code, or does it rely on binary blobs? Will the quality of the code make the grade, or will the community be expected to clean it up and maintain it?

When approached by Linux Magazine as to whether he has even looked at the code, Linus Torvalds (the father of Linux) replied:

“I haven’t. Mainly because I’m not personally all that interested in driver code (it doesn’t affect anything else), especially when I wouldn’t use it myself.

So for things like that, I just trust the maintainers. I tend to look at code when bugs happen, or when it crosses multiple subsystems, or when it’s one of the core subsystems that I’m actively involved in (ie things like VM, core device resource handling, basic kernel code etc).

I’ll likely look at it when the code is actually submitted to me by the maintainers (Greg [Kroah-Hartman], in this case), just out of morbid curiosity.”

So why the patch? Well, it contains three drivers which will enhance the performance of Linux when virtualized as a guest under Microsoft’s virtualization product, Hyper-V. Ahh, now the truth starts to emerge. The purpose of the code has nothing to do with being generous, but rather it is to ensure that Linux will run well under their own virtualization technology. Microsoft has well realized that the world is moving towards free software and that users are implementing Linux in their infrastructure.

Even though the motivation is a purely selfish one, is there anything wrong with that? Microsoft certainly plans to “outsmart open source” and this move should be seen in that light, but at the end of the day they are doing the unthinkable - contributing to free software - and that’s a win.

source

Ten of the most significant objects in science, engineering, technology and medicine were selected for the vote.

THE RESULTS

• 1st place - X-ray machines
• 2nd place - Penicillin
• 3rd place - DNA double helix
• 4th place - Apollo 10 capsule
• 5th place - V2 Rocket Engine
• 6th place - Stephenson's Rocket
• 7th place - Pilot ACE Computer
• 8th place - Steam Engine
• 9th place - Model T Ford
• 10th place - Electric Telegraph

Culture Secretary Ben Bradshaw said:

"The public's choice of the X-ray machine as the winner is testament to our insatiable curiosity to find out how things work."