SQL coding

Question 1

What is SQL aggregation? And what are examples?

Answer 1

An aggregating function takes a list of values and returns one value.

Examples: SUM, COUNT, MAX, MIN, ROUND, AVG

Question 2

What does the sql code “cross join” do?

Answer 2

Multiplies the number of ROWS in both tables. Note, rows are records, like they go down and up, don’t get them confused with columns.

Question 3

What does Select count(1) do?

Answer 3

Basically means “sum”, so it counts and displays the number of records which would’ve been produced.