COUNT ()

Syntax SQL COUNT (column_name)

SELECT COUNT(column_name) FROM table_name

Syntax SQL COUNT (*)

In the COUNT (*) - returns all records in the table below:

SELECT COUNT(*) FROM table_name

Syntax SQL COUNT (DISTINCT column_name)

COUNT (DISTINCT COLUMN_NAME) - returns only the different entries:

SELECT COUNT(DISTINCT column_name) FROM table_name

- Note: COUNT (DISTINCT) is working in ORACLE and Microsoft SQL Server, but not in Microsoft Access.

Example SQL COUNT (column_name)

Now we want to count the number of orders from the client "Nilsen".

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SELECT COUNT(Customer) AS CustomerNilsen FROM Orders
WHERE Customer='Nilsen'

Query Result:

Example SQL COUNT (*)

If you do not prescribe a WHERE clause E.

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SELECT COUNT(*) AS NumberOfOrders FROM Orders

The result will be:

Example SQL COUNT (DISTINCT column_name)

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SELECT COUNT(DISTINCT Customer) AS NumberOfCustomers FROM Orders

Query Result: