SQL Stored Procedures
A
stored procedure is a prepared SQL code that you can save, so the code can be
reused over and over again.
So
if you have an SQL query that you write over and over again, save it as a
stored procedure, and then just call it to execute it.
You
can also pass parameters to a stored procedure, so that the stored procedure
can act based on the parameter value(s) that is passed.
Stored
Procedure Syntax
CREATE PROCEDURE procedure_name
AS
sql_statement
GO;
Execute
a Stored Procedure
EXEC procedure_name;
Stored
Procedure Example
The
following SQL statement creates a stored procedure named
"SelectAllCustomers" that selects all records from the
"Customers" table:
Example
CREATE PROCEDURE SelectAllCustomers
AS
SELECT * FROM Customers
GO;
Execute
the stored procedure above as follows:
Example
EXEC SelectAllCustomers;
Stored
Procedure With One Parameter
The
following SQL statement creates a stored procedure that selects Customers from
a particular City from the "Customers" table:
Example
CREATE PROCEDURE SelectAllCustomers @City
nvarchar(30)
AS
SELECT * FROM Customers WHERE City
= @City
GO;
Execute
the stored procedure above as follows:
Example
EXEC SelectAllCustomers @City = 'London';
Stored
Procedure With Multiple Parameters
Setting
up multiple parameters is very easy. Just list each parameter and the data type
separated by a comma as shown below.
The
following SQL statement creates a stored procedure that selects Customers from
a particular City with a particular PostalCode from the "Customers"
table:
Example
CREATE PROCEDURE SelectAllCustomers
@City nvarchar(30),
@PostalCode nvarchar(10)
AS
SELECT * FROM Customers WHERE City
= @City AND PostalCode = @PostalCode
GO;
Execute
the stored procedure above as follows:
Example
EXEC SelectAllCustomers @City = 'London', @PostalCode = 'WA1 1DP';
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