SQL Alias

The SQL Alias syntax

The general syntax is:

1. SELECT column–name AS alias–name
2. FROM table–name alias–name
3. WHERE condition

 

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SQL Alias Examples

Problem: List total customers in each country.
Display results with easy to understand column headers.

1. SELECT COUNT(C.Id) AS TotalCustomers, C.Country AS Nation
2. FROM Customer C
3. GROUP BY C.Country

TotalCustomers and Nation are column aliases.
The table alias (C) in this example is not particularly useful.
Results: 21 records

TotalCustomers	Nation
3	Argentina
2	Austria
2	Belgium
9	Brazil
3	Canada

 

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Problem: List the total amount ordered by customer
with easy to read column headers

1. SELECT C.Id AS Identifier, C.LastName + ‘, ‘ + C.FirstName AS CustomerName,
2. SUM(O.TotalAmount) AS TotalSpent
3. FROM [Order] O JOIN Customer C ON O.CustomerId = C.Id
4. GROUP BY C.Id, C.LastName + ‘, ‘ + C.FirstName
5. ORDER BY TotalSpent DESC

The aliases significantly simplify writing the JOIN and ORDER BY clauses.
The C alias in C.Id helps identify the Customer Id rather then the Order Id.
Results: 89 records

Identifier	CustomerName	TotalSpent
63	Kloss, Horst	117483.39
71	Pavarotti, Jose	115673.39
20	Mendel, Roland	113236.68
37	McKenna, Patricia	57317.39
65	Wilson, Paula	52245.90