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Create parameterized VIEW in SQL Server 2008

开发者 https://www.devze.com 2023-01-31 09:16 出处:网络
Can we create parameterized开发者_JAVA技巧 VIEW in SQL Server 2008. Or Any other alternative for this ?Try creating an inline table-valued function. Example:

Can we create parameterized开发者_JAVA技巧 VIEW in SQL Server 2008.

Or Any other alternative for this ?


Try creating an inline table-valued function. Example:

CREATE FUNCTION dbo.fxnExample (@Parameter1 INTEGER)
RETURNS TABLE
AS
RETURN
(
    SELECT Field1, Field2
    FROM SomeTable
    WHERE Field3 = @Parameter1
)

-- Then call like this, just as if it's a table/view just with a parameter
SELECT * FROM dbo.fxnExample(1)

If you view the execution plan for the SELECT you will not see a mention of the function at all and will actually just show you the underlying tables being queried. This is good as it means statistics on the underlying tables will be used when generating an execution plan for the query.

The thing to avoid would be a multi-statement table valued function as underlying table statistics will not be used and can result in poor performance due to a poor execution plan.
Example of what to avoid:

CREATE FUNCTION dbo.fxnExample (@Parameter1 INTEGER)
    RETURNS @Results TABLE(Field1 VARCHAR(10), Field2 VARCHAR(10))
AS
BEGIN
    INSERT @Results
    SELECT Field1, Field2
    FROM SomeTable
    WHERE Field3 = @Parameter1

    RETURN
END

Subtly different, but with potentially big differences in performance when the function is used in a query.


No, you cannot. But you can create a user defined table function.


in fact there exists one trick:

create view view_test as

select
  * 
from 
  table 
where id = (select convert(int, convert(binary(4), context_info)) from master.dbo.sysprocesses
where
spid = @@spid)

... in sql-query:

set context_info 2
select * from view_test

will be the same with

select * from table where id = 2

but using udf is more acceptable


As astander has mentioned, you can do that with a UDF. However, for large sets using a scalar function (as oppoosed to a inline-table function) the performance will stink as the function is evaluated row-by-row. As an alternative, you could expose the same results via a stored procedure executing a fixed query with placeholders which substitutes in your parameter values.

(Here's a somewhat dated but still relevant article on row-by-row processing for scalar UDFs.)

Edit: comments re. degrading performance adjusted to make it clear this applies to scalar UDFs.


no. You can use UDF in which you can pass parameters.

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