在SQL Server中,如何在存储过程中传递可选参数?[关闭]

我试图传递可选变量。用户可以传递值,也可以不传递。

我尝试的是:

ALTER PROCEDURE spSampleProc
    @Alias NVARCHAR(25) = NULL,
    @CountDate DATE
AS
BEGIN
    SELECT
        *
    FROM
        ST
    INNER JOIN
        Item ON Item.id = st.itemid
    LEFT JOIN
        PIC_User ON ST.HandHeldNo = PIC_User.ID
    LEFT JOIN
        ViewRecord AS Alias ON Alias.itemid = item.ID
    LEFT JOIN
        Department ON Department.ID = item.DepartmentID
    LEFT JOIN
        Category ON category.id = item.CategoryID
    WHERE
        (@Alias IS NULL OR (Alias.Alias LIKE '%' + @Alias + '%'))
        AND ST.Date >= @CountDate
END

运行它:

EXEC spSampleProc @CountDate = '2018/09/01' @Alias = '6281063633419'

“@Alias”附近的语法不正确。