Aliases

SQL Aliases are a temporary name given to a table, view, or a column in a table for the specific query.  Aliases make columns easier to identify and allow for shorthand text.  Aliases are used to make complex SQL syntax easier to read where there are many joins and/or aggregations. The keyword “as” is used to denote an alias.

SQL Alias Column Syntax:

SELECT Column1 as NewName

FROM Table_Name

Alias Table Syntax:

SELECT

NewName .Column1,

NewName .Column2,

NewName .Column3

FROM Table_Name as NewName

Alias In Join Syntax:

SELECT

T1 .Column1,

T1.Column2,

T2.Column1,

T2.Column2

FROM Table1 as T1, Table2 as T2

WHERE T1.Column1=T2.Column1

Example:

Lets rename the column names of the following table

SalesReasonID	Name	ReasonType
1	Price	Other
2	On Promotion	Promotion
3	Magazine Advertisement	Marketing
4	Television Advertisement	Marketing
5	Manufacturer	Other
6	Review	Other
7	Demo Event	Marketing
8	Sponsorship	Marketing
9	Quality	Other
10	Other	Other

SELECT
SalesReasonID as ID,
Name as Sales_Reason_Name,
ReasonType as Sales_Reason_Type
FROM SalesReason

Results:

ID	Sales_Reason_Name	Sales_Reason_Type
1	Price	Other
2	On Promotion	Promotion
3	Magazine Advertisement	Marketing
4	Television Advertisement	Marketing
5	Manufacturer	Other
6	Review	Other
7	Demo Event	Marketing
8	Sponsorship	Marketing
9	Quality	Other
10	Other	Other

Table Alias Example:

SELECT
SR.SalesReasonID,
SR.Name,
SR.ReasonType
FROM SalesReason as SR

JOIN Alias Example:

SELECT
C.CustomerID,
C.StoreID,
S.ID,
S.Name
FROM Customer as C, Store as S
WHERE C.StoreID=S.ID

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