New Feature: Playlist Center! Pick a topic and let our playlists guide the way.

Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Selecting columns

From: MySQL Essential Training

Video: Selecting columns

A given table may have a lot of columns and you will often be interested in And we also get all of the columns, if I I could say Code AS ISO, because that's an ISO code.

Selecting columns

A given table may have a lot of columns and you will often be interested in only some of them fortunately, selecting particular columns is easy and here is how it's done. Here I have SID opening my browser and I'm going to select the world database, and if I just select like this, SELECT * FROM Country ORDER BY Code; and I'll press the Go button. You see we get all 239 rows.

And we also get all of the columns, if I scroll off to the side here, you see there's even more. The asterisk is in the place where you would list the columns you wanted returned by the query the asterisk is simply the wildcard that means all of the columns. You can select particular columns by listing them in the Select statement in the place where the asterisk is. So if I come over here I can say Name, Code, Region, Population, and I press Go.

And I just get those columns, Name, Code, Region, and Population in the order that I specified them in the SELECT statement. If you would like to return different names in your column headers, you can do so with the AS clause after the column name like this. I could say Name AS Country. I could say Code AS ISO, because that's an ISO code. I could say population AS Pop, like that and if I press Go, you see now we have country, ISO, region, pop in our headers.

Now, the column headers are actually the names returned by the database interface, so they're commonly used in your code. They're also used in SQL to specify intermediate results. So the AS clause can be important in preventing namespace collision. You'll see more examples of this later in the course. It's also worth noting that the AS clause is often omitted. If I take out the word AS and just list the other name right next to the column name, it has exactly the same result.

So the AS keyword is optional, I very much prefer to use the AS keyword, because it makes the code more readable. It makes it more obvious what's going on and also if I were to happen to list two columns and simply forget the comma, but I have this AS clause here, it comes up as a syntax error and I get an error. But if I don't have the AS clause there, then what I'll get is the name column with the word Code at the top of it.

So, using the AS clause all the time, it's much less ambiguous. And it's much more clear what you mean and it's actually even less prone to error. So, I suggest that you always use the AS keyword although you need to be aware that you'll see a lot of code out there where people omit the AS keyword. I think it's lazy to do so and I wish it was required personally. So it's easy to select particular columns from a table in SQL, this is a feature you'll use a lot, and you'll see a lot in this course.

Show transcript

This video is part of

Image for MySQL Essential Training
MySQL Essential Training

60 video lessons · 4678 viewers

Bill Weinman

Expand all | Collapse all
  1. 4m 22s
    1. Welcome
      1m 3s
    2. Using the exercise files
      1m 31s
    3. What is MySQL?
      1m 48s
  2. 45m 37s
    1. Installation overview
      3m 16s
    2. Installing XAMPP on Windows
      5m 55s
    3. Installing XAMPP on the Mac
      6m 38s
    4. Setting up MySQL users
      11m 31s
    5. Installing SID on Windows
      5m 43s
    6. Installing SID on the Mac
      6m 6s
    7. Installing time zone support in MySQL on Windows
      6m 28s
  3. 45m 43s
    1. The SELECT statement
      3m 57s
    2. Selecting rows
      4m 57s
    3. Selecting columns
      3m 8s
    4. Sorting results with ORDER BY
      2m 58s
    5. Filtering results with WHERE
      3m 52s
    6. Filtering results with LIKE and IN
      3m 41s
    7. Filtering results with regular expressions
      8m 21s
    8. Inserting rows
      4m 9s
    9. Updating rows
      2m 21s
    10. Deleting rows
      2m 25s
    11. Literal strings
      3m 12s
    12. Understanding NULL
      2m 42s
  4. 41m 47s
    1. Creating a database
      4m 30s
    2. Creating a table
      7m 18s
    3. Creating indexes
      6m 8s
    4. Controlling column behavior with constraints
      4m 46s
    5. Creating an ID column
      6m 58s
    6. Using foreign key constraints
      7m 58s
    7. Altering a table
      4m 9s
  5. 28m 56s
    1. What are data types?
      4m 1s
    2. Numeric types
      5m 21s
    3. String types
      2m 58s
    4. Date and time types
      7m 2s
    5. Bit type
      2m 26s
    6. Boolean values
      2m 15s
    7. Enumeration types
      4m 53s
  6. 32m 34s
    1. String functions
      6m 57s
    2. Numeric functions
      6m 2s
    3. Date and time functions
      4m 12s
    4. Time zones in MySQL
      3m 37s
    5. Formatting dates
      1m 51s
    6. Aggregate functions
      5m 45s
    7. Flow control with CASE
      4m 10s
  7. 7m 6s
    1. Maintaining database integrity with transactions
      4m 46s
    2. Using transactions for performance
      2m 20s
  8. 16m 49s
    1. Updating a table with a trigger
      5m 11s
    2. Preventing automatic updates with a trigger
      7m 29s
    3. Logging transactions with a trigger
      4m 9s
  9. 14m 11s
    1. Creating a simple subselect
      3m 23s
    2. Searching within a result set
      3m 53s
    3. Creating a view
      3m 32s
    4. Creating a joined view
      3m 23s
  10. 12m 26s
    1. Understanding MySQL stored routines
      2m 0s
    2. Creating a stored function
      4m 34s
    3. Creating a stored procedure
      5m 52s
  11. 14m 4s
    1. The multi-platform PDO interface
      3m 44s
    2. Executing the SQL
      4m 8s
    3. Implementing auto-increment IDs
      2m 3s
    4. Using a stored funciton
      4m 9s
  12. 1m 3s
    1. Goodbye
      1m 3s

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes changes my life forever. @JosefShutter
@lynda is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold

Are you sure you want to delete this note?


Thanks for signing up.

We’ll send you a confirmation email shortly.

Sign up and receive emails about and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from

Sign up and receive emails about and our online training library:

Here’s our privacy policy with more details about how we handle your information.

submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.