Question

I have a table (“presentations”) with these columns:

PresentationTitle | Speaker1 | Speaker2 | Speaker3

This works great for listing all of the presentation titles like this on my “Presentations” page:

Presentation Number One
  by:
  John Smith
  Pocahontas Smith
  John Rolfe

Presentation Number Two
  by:
  Grandmother Willow

Presentation Number Three
  by:
  Chief Powhatan
  Kocoum Derpyderpderp

But now, for my “Speakers” page, I need to list all of the speakers–independent of each other–in alphabetical order. Like this:

Chief Powhatan
Grandmother Willow
John Rolfe
John Smith
Kocoum Derpyderpderp
Pocahontas Smith

What’s the best way to do this?

Another note–In my real-life table, the speaker1 column has lots more columns attached to it– “middlename”, “lastname”, “headshot”, “age”… and speaker2 has “middlename2”, “lastname2”, “headshot2,” etc… I need to keep these pieces of info attached to those speakers.

Thanks in advance for helping a big noob like me 🙂

Answer 1

You should rethink your database design. A better table layout would be something more like:

CREATE TABLE presentations (
    presentationID INT,
    presentationTitle VARCHAR(200),
    PRIMARY KEY (presentationID)
);

CREATE TABLE speakers (
    speakerID INT,
    firstName VARCHAR(32),
    middleName VARCHAR(32),
    lastName VARCHAR(32),
    headshot BLOB,
    age TINYINT UNSIGNED,
    PRIMARY KEY (speakerID)
);

CREATE TABLE presentationSpeakers (
    presentationID INT,
    speakerID INT
);

Then you can do a query like this to list all speakers from a particular presentation in alphabetical order by first name:

SELECT
    s.firstName,
    s.lastName
FROM
    presentationSpeakers ps
    INNER JOIN presentations p ON ps.presentationID = p.presentationID
    INNER JOIN speakers s ON ps.speakerID = s.speakerID
WHERE
    p.presentationTitle = 'Presentation Number One'
ORDER BY
    s.firstName, s.lastName

Or a query as simple as this for all speakers in alphabetical order by first name:

SELECT firstName, lastName FROM speakers ORDER BY firstName, s.lastName

This is better for many reasons. Having a bunch of extra columns for every speaker will be difficult to deal with (which is the trouble you’re having now), plus you’ll have a ton of columns which may not be used (depending on the number of speakers), which may waste space, and another big reason…what if you get a presentation in which there are more speakers than you have columns?

My way is much more flexible and much easier to perform simple operations (like sorting). You can have any number of speakers for each presentation, and there is no wasted space taken up with unused columns.