SQL: Functioning in the Real World - Count Distinct
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Let's step away from the lawsuit scenario for a moment. Let's add a new column to our table called Position. Fill in your database with the added values below.
Name | Age | Salary | Position |
Ang Ree | 92 | $12,000 | Director |
Godzilla Nokamura | 45 | $50,000 | Villain |
Mothra Fujiyama | 27 | $80,000 | Villain |
King Kong Wong | 19 | $100,000 | Hero |
Go-Go Roboto | 29 | $100,000 | Actor created solely for toy sales |
If we wanted to know how many unique positions there were (or any other unique items) we could use the Count(Distinct) function. As you can see, there are presently 5 positions in the company. What we want to know though is how many positions there are that don't duplicate themselves.
Select Count (Distinct Position) from Employees
The result:
4
This is because the Villain position is a duplicate, and thus one value is not unique.
Next: Minimum and Maximum >>
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