Hello I am new in creating stored procedure can you help me how to do this. Error: Incorrect syntax near the keyword 'AS'. Must declare scalar variable @Serial.
CREATE PROCEDURE sp_SIU
    -- Add the parameters for the stored procedure here
    @Serial varchar(50),
    @Part varchar(50),
    @Status varchar(50),
AS
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    /*SET NOCOUNT ON;*/
    -- Insert statements for procedure here
    --where in my form if i enter serial number it will show select values  
    Select SerialNumber,PartNumber,Status from Table1 where SerialNUmber = @Serial
    --Then if is correct it will Update Status on combobox
       Update Table1 SET
               Status=@Status
                 where SerialNumber=@SerialNumber
    --then Insert Serial Number,Parnumber to Table 2
        DECLARE @Count int
    select @Count = Count(SerialNumber) from Table1 WHERE SerialNumber = @Serial
    IF @Count = 0 
        BEGIN
                INSERT INTO Table2 (SerialNumber,PArtNumber) 
                VALUES 
                (@Serial, @Part)
        END 
        RETURN @Count
    RETURN
Edit: Moved Updated info posted as an answer into Question
Oops my post is not that kind a miss. It is possible to join this 3 sql string in one stored procedure?
Scenario:
{
What i have to do in my form is that i will enter serial number to txtserial.text by using the select sql it will show serialnumber,partnumber and status on lblserial.text,lblpartnumber.text and lblstatus.text.
And i will compare:
txtserial.text == lblserial.text
txtpartnumber.text == lblpartnumber.text
for my error handler.
{
Select SerialNumber,PartNumber,Status from Table1 where SerialNUmber = @Serial
}
Then if they are equal then: I will update my Status from cbostatus.text if serial and part is correct then use sql upate.
{
Update Table1 SET
               Status=@Status,
               Modifiedby=@username,
               DateModified=@Date
                 where SerialNumber=@Serial
}
Then insert serialnumber, using sql insert to another table.
{
 INSERT INTO Table2 (SerialNumber,DateCreated,Createdby) 
                VALUES 
                (@Serial,@date,@username)
}
something likethis. ")