Week 2

Question 1

What is select used for?

Answer 1

to select a subset of data from a table

Question 2

What is a projection?

Answer 2

used to select a subset of columns from a table

Question 3

What does ordering and distinct mean?

Answer 3

used to order the results and remove duplicates

Question 4

What do joins do?

Answer 4

they combine data from multiple tables to retrieve desired information

Question 5

What are the three different types of joins in sql?

Answer 5

inner, self, and outer

Question 6

What does the join command return?

Answer 6

rows that have matching values in both tables

Question 7

What does ‘as’ represent in sql?

Answer 7

we are giving something an alias

Question 8

What does an outer join return?

Answer 8

rows that match the condition and exist in both tables

Question 9

What does the left join return?

Answer 9

everything from table 1 and that is matching between table 1 and table 2

Question 10

What does a right join return?

Answer 10

everything from table 2 and that is matching between table 1 and table 2

Question 11

What does a full outer join return?

Answer 11

everything in both tables; table 1 rows, table 2 rows, matching from both