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SELECT command is the main SQL to query a database.

Syntax

SELECT [ ALL | DISTINCT | TOP ] column_name [ AS alias_name]
FROM table_1 [, table_2, ... , table_n ]
[ JOIN join_condition]
[ WHERE search_condition ]
[ GROUP BY group_by_expression ]
[ HAVING search_condition ]
[ ORDER BY order_expression [ ASC | DESC] ]

A simple table (Employee)

Some examples:

SELECT * FROM Employee

Returns the following result:

An example with alias and data sorting

SELECT Surname AS Employee, City 
FROM Employee 
ORDER BY Surname

Returns the following result:

Two examples with a selection condition:

SELECT * FROM Employee
WHERE Age > 30

Returns the following result:

SELECT * FROM Employee
WHERE Age > 30 AND Salary < 1600

Returns the following result: