PostgreSQL exercises

Question

You want to print out a list of all of the facilities and their cost to members. How would you retrieve a list of only facility names and costs?

Schema reminder ▼

Expected Results

name	membercost
Tennis Court 1	5
Tennis Court 2	5
Badminton Court	0
Table Tennis	0
Massage Room 1	35
Massage Room 2	35
Squash Court	3.5
Snooker Table	0
Pool Table	0

Your Answer Hint Help Save Run Query

Answers and Discussion Show

select name, membercost from cd.facilities;

For this question, we need to specify the columns that we want. We can do that with a simple comma-delimited list of column names specified to the select statement. All the database does is look at the columns available in the FROM clause, and return the ones we asked for, as illustrated below

Specifying column names to a select statement

Generally speaking, for non-throwaway queries it's considered desirable to specify the names of the columns you want in your queries rather than using *. This is because your application might not be able to cope if more columns get added into the table.

Previous Exercise

Next Exercise

The select statement allows you to specify column names to retrieve.

Keyboard shortcuts:

Alt-h: Show/Hide Help menu
Alt-r: Run query
Alt-x: Run selected text as query
Alt-s: Run query by cursor (delimited by whitespace/semi-colon)

Other hints:

You can double click on each of the panes of Expected Result/Your answer to quickly resize them.
If you have trouble remembering the database schema, you can leave this popup open while you work on your answer.
Don't forget to use the hint button if you're stuck!