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Oracle SQL Tutorial 9 - Intro to Queries

471 ratings | 32754 views
This video is for beginners who have never worked with SQL Developer, and we are going to teach how to begin writing queries. So the queries we are going to start with are queries when we give the database an expression and it will return back some kind of value. The most common keyword you are going to need to know for Oracle is SELECT. SELECT is the command we use to get data from the database. Even though we have not really put any data in our database, we can still use the SELECT statement to get data. That's because the database is capable of doing more than just creating tables and retrieving data from tables. So our first goal is to essentially write a Hello World, which just displays the text hello world to us. A good place to start is with: SELECT 'Hello World' This would actually work for many database management systems, but when you run it you will get an error. This actually doesn't work with Oracle, it will tell us we always need the FROM keyword. To get around this, there is a magical table called DUAL. We can put anything we want to SELECT and then say FROM DUAL and it will work. SELECT 'Hello World' FROM DUAL We can also do math: SELECT 1+1 FROM DUAL And we can run even run functions: SELECT SYSTIMESTAMP FROM DUAL To put all of this together, you can grab all of this data at the same time using commas to separate different columns from our generated table: SELECT 'Hello World', 1+1, SYSTIMESTAMP FROM DUAL Support me on Patreon: http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
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Text Comments (11)
Salma Mohmed (2 months ago)
by no means this queries
A C (4 months ago)
YAY! I finally did something.
Scott M. (6 months ago)
Good video, but it would have been helpful if you showed how you got to Query Builder in Oracle SQL Developer. I had to look it up on the Internet of how to get to the Query Builder in Oracle SQL Developer.
Stepheno Maleche (9 months ago)
it seems am stuck. how do we get the developer to start in the first place?
manohore (10 months ago)
Thanks for the videos. They're informative and not too technical. Now, get a haircut.
kareem jeiroudi (1 year ago)
Finally! A practice video!
Martina Pax (1 year ago)
Hey! i like your videos WHERE ARE YOU FROM, i speak spanish and i usually i can't understand the details but in this case is clear. THANKS A LOT :)
dawda sanneh (2 years ago)
The original Caleb. You are so effing cool dude. I'm from London. My son thinks you gonna make the coolest Professor. Prof. Cay!
Veronica Humble (2 years ago)
This is what I've been waiting for! And the sound was very good. I thought it was one of your better sounding videos.
zeeshan ali (1 year ago)
Hi Caleb ive been watching ur videos u have done a great job thank you. May i have ur email id so i could ask u questions? Bc i dont belong to IT field so when i see the video i have many queries in mind. My email id is [email protected]
Caleb Curry (2 years ago)
Thank you! I'm glad to hear that you are liking the new videos, and thank you for the generous gift. :)

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