SqlSever 自定义函数创建 - 标量函数_怎么把函数改写为标量函数的方法

-- ================================================
-- Template generated from Template Explorer using:
-- Create Scalar Function (New Menu).SQL
--
-- Use the Specify Values for Template Parameters 
-- command (Ctrl-Shift-M) to fill in the parameter 
-- values below.
--
-- This block of comments will not be included in
-- the definition of the function.
-- ================================================
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author: <Author,,Name>
-- Create date: <Create Date, ,>
-- Description: <Description, ,>
-- =============================================
CREATE FUNCTION GetDescr(@a varchar(200))       ///（GetDescr()函数名   @a 传参变量  varchar(200) 传参类型）


RETURNS varchar(2000)   ///函数返回值类型
AS
BEGIN
-- Declare the return variable here
DECLARE  @s varchar(2000) set @s=''
-- Add the T-SQL statements to compute the return value here
SELECT @s=@s+isnull(item_descr_c,'') +',' FROM [Ipdb].[dbo].[oatask_item_set]
left join oa_task_item f on f.oatask_id = @a 
        where item_id=f.descritem_id                               ///sql语句（获取一列数据，将该数据转换成字符串）
-- Return the result of the function
RETURN @s


END

GO

sql语句调用

dbo.GetDescr(' ') as T

直接调用