Dynamic SQL Not working - Complies , but errors out - sql-server

Question

CREATE TABLE [dbo].[TSQL_DLOOKUP](
[LookUpTable] [nchar](10) NULL,
[LookUpField] [nchar](10) NULL,
[LookUpValue] [nchar](10) NULL,
[LookUpDecode] [nchar](20) NULL
) ON [PRIMARY]
GO
The procedure:
ALTER PROCEDURE [dbo].[MyDLookUp]
#LookUpValue NCHAR(10),
#LookUpTable NCHAR(10),
#LookUpField NCHAR(10)
AS
BEGIN
DECLARE #SQLQuery AS NVARCHAR(500)
DECLARE #ParameterDefinition AS NVARCHAR(100)
/* Build Transact-SQL String by including the parameter */
SET #SQLQuery = 'SELECT LookUpDecode FROM TSQL_DLOOKUP WHERE LookUpTable = #LookUpTable AND LookUpValue = #LookUpValue AND LookUpField =#LookUpField'
/* Execute Transact-SQL String */
EXECUTE sp_executesql #SQLQuery, #LookUpValue,#LookUpTable,#LookUpField
END
enter code here To run:
DECLARE #return_value int
EXEC #return_value = [dbo].[MyDLookUp]
#LookUpValue = N'F',
#LookUpTable = N'LCLASS',
#LookUpField = N'CLASS'
SELECT 'Return Value' = #return_value
The error: Msg 102, Level 15, State 1, Line 1
Incorrect syntax near 'F'.
Msg 137, Level 15, State 2, Line 1
Must declare the scalar variable "#LookUpTable".
The code compiles, but will not run. Please help.
The idea here is to as accurately as possible replicate the MSACCESS DLOOOKUP function. I am on a project in which a lot of repeated SQL statements exist where the coder before me did it this way, I need to simplify things.

Answer 1

As said by LAMAK Clearly there is no need of Dynamic query here u can do the same by using staic query!!
SELECT lookupdecode
FROM tsql_dlookup
WHERE lookuptable = #LookUpTable
AND lookupvalue = #LookUpValue
AND lookupfield = #LookUpField
Function to do the same job
CREATE FUNCTION dlookup(#LookUpValue NCHAR(10),
#LookUpTable NCHAR(10),
#LookUpField NCHAR(10))
RETURNS nchar
AS
BEGIN
declare #lookupdecode nchar(50)
SELECT top 1 #lookupdecode = lookupdecode
FROM tsql_dlookup
WHERE lookuptable = #LookUpTable
AND lookupvalue = #LookUpValue
AND lookupfield = #LookUpField
RETURN #lookupdecode
END;

Answer 2

You are missing the #params parameter from the sp_executesql command which defines the parameters being passed in:
EXECUTE sp_executesql #SQLQuery,
N'#LookUpValue [nchar](10),#LookUpTable [nchar](10),#LookUpField [nchar](10)',
#LookUpValue,#LookUpTable,#LookUpField

Answer 3

As other said in this case there is no need of dynamic sql as it can be executed directly.
For answer to your question, see below.
The parameter definition needed to be passed as an argument to sp_executesql SP to pass parameters to a dynamic query http://msdn.microsoft.com/en-us/library/ms188001.aspx.
So, your new SP will be as follows
alter PROCEDURE [dbo].[MyDLookUp]
#LookUpValue NCHAR(10),
#LookUpTable NCHAR(10),
#LookUpField NCHAR(10)
AS
BEGIN
DECLARE #SQLQuery AS NVARCHAR(500)
DECLARE #ParameterDefinition AS NVARCHAR(100)
/* Build Transact-SQL String by including the parameter */
SET #SQLQuery = 'SELECT LookUpDecode FROM TSQL_DLOOKUP WHERE LookUpValue = #LookUpValue AND LookUpTable = #LookUpTable AND LookUpField =#LookUpField'
DECLARE #ParmDefinition nvarchar(500);
SET #ParmDefinition = N'#LookUpValue NCHAR(10), #LookUpTable NCHAR(10), #LookUpField NCHAR(10)';
/* Execute Transact-SQL String */
EXECUTE sp_executesql #SQLQuery, #ParmDefinition, #LookUpValue,#LookUpTable,#LookUpField
END

Answer 4

Try this Code, if this work for you because there is no need to use Dynamic SQL for simple select statment
---------------------------------------Stored Procedure
Alter PROCEDURE [dbo].[MyDLookUp] --[dbo].[MyDLookUp] 1,2,3
#LookUpValue NCHAR(10),
#LookUpTable NCHAR(10),
#LookUpField NCHAR(10)
AS
BEGIN
SELECT LookUpDecode FROM TSQL_DLOOKUP
WHERE LookUpTable = #LookUpTable AND LookUpValue = #LookUpValue AND LookUpField =#LookUpField
END