Basic functions

#SELECT Statement
# Top, Distinct, Count, As, Max, Min, Avg

SELECT *
FROM EmployeeDemographics
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# Top function, say top 3.
SELECT TOP 3 *
FROM EmployeeDemographics

# Error message with Top function, using LIMIT function instead.
SELECT *
FROM EmployeeDemographics
LIMIT 3
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# Distinct function. Used to get unique values in a specific column
SELECT DISTINCT (LastName)
FROM EmployeeDemographics
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#Count function. Returns non-null values in a column. 
SELECT COUNT(FirstName)
FROM EmployeeDemographics
#Note; for COUNT to work, no space between function & parenthesis
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#As function. Used to rename a column in a table
SELECT COUNT(FirstName) AS LastnameCount
FROM EmployeeDemographics
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SELECT *
FROM EmployeeSalary

#Max function
SELECT MAX(Salary)
FROM EmployeeSalary

#Min function
SELECT MIN(Salary)
FROM EmployeeSalary

#Avg function
SELECT AVG(Salary)
FROM EmployeeSalary