将 SQL 过程转换为函数

Question

create function fiyathesapla(@StartDate datetime2(5),@EndDate datetime2(5),@kodu nvarchar(max))
returns table
as
return (

WITH theDates AS
     (SELECT @StartDate as theDate
      UNION ALL
      SELECT DATEADD(day, 1, theDate)
        FROM theDates
       WHERE DATEADD(day, 1, theDate) <= @EndDate
     )
SELECT SUM( v_period.fiyat-((v_period.fiyat/100)*v_period.indirim))  FROM theDates,v_period  WHERE tarih1<=theDates.theDate and tarih2>=theDates.theDate  and  vkodu=@kodu
)
go

---错误代码---

Msg 4514, Level 16, State 1, Procedure fiyathesapla, Line 6 [Batch Start Line 0] CREATE FUNCTION failed because a column name is not specified for column 1.

我在尝试创建函数时遇到此错误。它有助于通过按天计算输入的两个日期来计算价格。但是当我创建存储过程时它起作用了。我想创建一个函数，我该如何编辑它。

---正常运行的过程代码---

USE [villapaket1]
GO
/****** Object:  StoredProcedure [dbo].[FN_fiyat]    Script Date: 30.09.2020 16:18:46 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[FN_fiyat] @StartDate datetime2(5),@EndDate datetime2(5),@kodu nvarchar(max)
AS

WITH theDates AS
    (SELECT @StartDate as theDate
     UNION ALL
     SELECT DATEADD(day, 1, theDate)
       FROM theDates
      WHERE DATEADD(day, 1, theDate) <= @EndDate
    )
SELECT SUM( v_period.fiyat-((v_period.fiyat/100)*v_period.indirim))  FROM theDates,v_period  WHERE tarih1<=theDates.theDate and tarih2>=theDates.theDate  and  vkodu=@kodu

Answer 1

看起来数据库引擎告诉您 SUM( v_period.fiyat-((v_period.fiyat/100)*v_period.indirim))（= 最后 select 的第一列）需要一个别名。这不是在函数外部显示结果所必需的，但是 return 具有有效列名的table 所必需的。

下面和 this fiddle.

中的小数据集和简单（但相似）函数的问题再现

示例数据

create table MyTable
(
  id int
);

insert into MyTable (id) values
(100), (101), (102);

选择

with cte as
(
  select id-100 as NewId from MyTable
)
select sum(cte.NewId) --> no column alias, works fine (result table has unnamed column)
from cte;

函数

create function MyFunction()
returns table
as return
(
  with cte as
  (
    select id-100 as NewId from MyTable
  )
  select sum(cte.NewId) --> no column alias, does NOT work
  from cte
);

CREATE FUNCTION failed because a column name is not specified for column 1.

已更新为工作函数：

create function MyFunction()
returns table
as return
(
  with cte as
  (
    select id-100 as NewId from MyTable
  )
  select sum(cte.NewId) as IdSum --> with column alias
  from cte
);

将 SQL 过程转换为函数

Convert SQL procedure to function

tsql

sql-server

stored-functions