Join Bill Weinman for an in-depth discussion in this video Conditional expressions with CASE, part of SQL Essential Training.
…SQL provides a form of conditional expression.…It's a little cumbersome, but here's how it works.…I'm going to use the test.db database.…I'm going to copy and paste from the exercise files for…chapter 2 here, under CASE this is around line 157.…I'm going to grab these 3 lines that create a table and insert a row.…The table is called bull test, going to paste this into our box here and press go.…Boolean's in SQL lite are integers with a value…of 0 for false and anything else for true.…
So Boolean's are often handled like this with an integer column.…And so I've inserted one row and there's a one or a true in column A.…And a zero or a false in column B.…And so we'll leave that select there.…And I'm going to create another select after it.…With a case statement in it.…And it's probably easiest to just copy and paste this as well.…And this case expression, it's not actually a…statement, it's an expression, is a conditional expression.…So, how this works, it's introduced with case and it ends with end.…
And the when clause tests for true or false.…
- Understanding SQL terminology and syntax
- Creating new tables and records
- Inserting and updating data
- Writing basic SQL queries
- Sorting and filtering
- Accessing related tables with JOIN
- Working with strings
- Finding the numeric type of a value
- Using aggregate functions and transactions
- Updating a table with triggers
- Creating views
Skill Level Beginner
Q: For Mac OS X: When I try to start the Apache Web Server from the XAMPP control panel, it doesn't start, and when I open "localhost" in my web browser, I see a white screen that says "It Works!" instead of the XAMPP page.
sudo apachectl stop
Q: I'm on a Mac, and I get an error in SID that says "attempt to write a read only database." How can I fix this?
A: This usually means that the database folder does not have sufficient permissions for writing by the web user. This can happen if you create the SQL folder new, rather than copying it from the Exercise Files. Here's how to fix this:
- Open a Finder window and Navigate to /Applications/XAMPP/htdocs/SQL
- Control-click on the SQL folder and select "Get Info" from the context menu.
- Under "Sharing and Permissions" (you may need to open the disclosure triangle), in the "everyone" row, select "Read & Write."Then you can close the Info window.
- Now repeat the process for the three *.db files inside the folder.
1. SQL Quick Start
Understanding joins2m 23s
Dates and times1m 59s
10. Subselects and Views
11. A Simple CRUD Application
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