What You Will Learn in This SQL Course: 10 practice questions

Question 1 of 10

A lesson of this course has just opened. In which order do its parts arrive?

1. ASlides and quick checks, then ten questions, then practice where there is one
2. BOne long page of text, with the questions replacing the example tables
3. CA six-step practice on its own, with no slides and no result tables
4. DTen questions first, then the slides, and no hands-on practice at all

Question 2 of 10

Only the tracks table is in play. Which job does block one already cover?

1. AShowing each track next to the name of the artist who recorded it
2. BSaving the query under a name so that it can be read like a table
3. CFiltering its rows by a condition and sorting them by name
4. DReplacing the whole table with one line holding the average price

Question 3 of 10

Which data do the lessons, the questions and the practice of this course work on?

1. AOne store for the slides and another one for the practice
2. BA new set of tables invented for each block
3. CA store that the learner must supply before starting
4. DThe same small music store, in every lesson of the course

Question 4 of 10

Album titles are kept in `albums` and artist names in `artists`. A query has to return the two rows `For Those About To Rock` and `Let There Be Rock` for the artist AC/DC. Which block supplies that skill?

1. ABlock three, because counting the albums returns the titles
2. BBlock one, because one table can be filtered and sorted
3. CBlock six, because the two reads belong to one transaction
4. DBlock two, which joins the two tables on the shared artist number

Question 5 of 10

Six album rows go into a query and the result holds four rows: `AC/DC 2`, `Accept 2`, `Aerosmith 1`, `Alanis Morissette 1`. Which block explains why six rows became four?

1. ABlock three, where rows are grouped and counted
2. BBlock seven, where a view is read like a table
3. CBlock four, where a query is placed inside another
4. DBlock one, where rows are filtered one by one

Question 6 of 10

In `SELECT name FROM artists WHERE NOT EXISTS (SELECT 1 FROM albums WHERE albums.artist_id = artists.artist_id)`, the inner query runs once for each artist. What does the outer query do with its answer?

1. AIt sorts the artists before the inner query runs
2. BIt counts the albums and returns a total per artist
3. CIt replaces the artists table with the albums table
4. DIt keeps the artists for which no album was found

Question 7 of 10

A table is created with `CREATE TABLE label_notes (artist_id INTEGER PRIMARY KEY, note VARCHAR(40) NOT NULL, active INTEGER DEFAULT 1)`. The statement `INSERT INTO label_notes (artist_id, note) VALUES (1, 'back catalogue')` names two columns, and the stored row shows `active` as 1. Which rule filled it?

1. AThe database copied the value from another table
2. BThe value was calculated from the primary key column
3. CThe insert ran twice and the two rows were merged
4. DThe third column was given a default value

Question 8 of 10

A transaction raises the price of track 8, sets `SAVEPOINT s1`, raises the price of track 9, and then runs `ROLLBACK TO SAVEPOINT s1` and `COMMIT`. Which price changes are stored at the end?

1. AOnly the first change, because the second was undone
2. BBoth changes, because both updates ran without an error
3. COnly the second change, because the later update wins
4. DNeither change, because the rollback cancelled the group

Question 9 of 10

A learner of this course can already filter and sort one table. Which topics do blocks two and three teach next, in that order?

1. AGrouping and counting, and only then joining the tables
2. BCreating a table, and then reading it through a view
3. CJoining the tables, and then grouping and counting them
4. DOpening a transaction, and then setting a savepoint

Question 10 of 10

A long query over `tracks` is saved with `CREATE VIEW standard_tracks AS`, and an index is added to the same table. What changes for the person who later reads that view?

1. ANothing changes, because a view has to be written out again each time
2. BThe rows returned change, because the index filters them
3. CThe name is shorter, and a suitable index may speed up the search
4. DThe column names change, because the view renames the table