在SQL Server 2016中使用本地編譯修改表值函數時出錯

Question

我有以下腳本來改變我的本地編譯函數。我希望它返回一個表。我也正在從單一聲明變成多聲明。所以我將returns更改爲begin atomic。

ALTER FUNCTION [dbo].[MovieSimularity] 
( 
    @movieID int 
) 
RETURNS @result Table (movieID int, distance int) 
WITH Native_Compilation, SCHEMABINDING 
as 
Begin ATOMIC WITH (TRANSACTION ISOLATION LEVEL = SNAPSHOT, LANGUAGE = N'English') 
--begin 

    declare @m int 
    declare @countZero int 
    declare @r Table (movieID int, distance int) 
    declare cur cursor local for 
     select movieID 
     from dbo.Movies 
     where movieID != @movieID and dbo.CompareMovieHashes(@movieID, movieID) = 1 

    open cur 
    fetch next from cur into @m 
    while @@FETCH_STATUS = 0 
    begin 
     insert into @r 
      select @m, dbo.MovieEuclideanDistance(@movieID,@m) as distance 

     set @countZero = (select count(*) from @r where distance = 0) 
     if(@countZero > 5) 
      break 

     fetch next from cur into @m 
    end 
    close cur 
    deallocate cur 

    return 
     select top(5) * 
     from @r 
     order by distance 
end 

執行給了我以下錯誤：

Msg 487, Level 16, State 1, Procedure MovieSimularity, Line 12 [Batch Start Line 7] 
An invalid option was specified for the statement "CREATE/ALTER FUNCTION". 
Msg 319, Level 15, State 1, Procedure MovieSimularity, Line 13 [Batch Start Line 7] 
Incorrect syntax near the keyword 'with'. If this statement is a common table expression, an xmlnamespaces clause or a change tracking context clause, the previous statement must be terminated with a semicolon. 
Msg 102, Level 15, State 1, Procedure MovieSimularity, Line 44 [Batch Start Line 7] 
Incorrect syntax near 'end'. 

我不知道是什麼問題。請幫助

Answer 1

BEGIN ATOMIC是ANSI SQL標準的一部分。 SQL Server在本機編譯的存儲過程, 以及本機編譯的標量用戶定義的函數的頂級處支持 原子塊。有關這些函數的更多信息，請參閱標量用戶定義 用於內存中OLTP的函數。有關這些函數的更多信息，請參見 。

https://docs.microsoft.com/en-us/sql/relational-databases/in-memory-oltp/atomic-blocks-in-native-procedures

原子不被表值函數支持（按照文檔），只能是標量值函數。

這個查詢有什麼問題？你爲什麼需要光標？

DECLARE @movieID INT = 1; 
SELECT TOP(5) 
     movieID 
    , dbo.MovieEuclideanDistance(@movieID,m.movieID) AS distance 
FROM 
    dbo.Movies 
WHERE 
    movieID != @movieID 
    AND dbo.CompareMovieHashes(@movieID, movieID) = 1 
ORDER BY 
    distance 

這裏是一個解決方案，您的0距離問題，而不使用遊標或循環。根據您的需求進行調整。

DECLARE 
    @rowsToCalculate INT = 5 
    , @currentX DECIMAL(8,5) 
    , @currentY DECIMAL(8,5) 
; 

-- Get the current movie's X and Y coordinates 
SELECT 
    , @currentX = CoordX 
    , @currentY = CoordY 
FROM 
    dbo.Movies 
WHERE 
    MovieID = @movieID 
; 

-- First get the list with distance 0 (x and y coordinates are equal) 
INSERT INTO @result (MovieID int, Distance int) 
SELECT TOP(@rowsToCalculate) 
    MovieID 
    , 0 AS Distance 
WHERE 
    CoordX = @currentX 
    AND CoordY = @currentY 
    AND MovieID != @movieID 
    AND dbo.CompareMovieHashes(@movieID, MovieID) = 1 
; 

-- Figure out how many records do we need and get them if there is any. 
SET @rowsToCalculate = @rowsToCalculate - (SELECT COUNT(*) FROM @result); 

IF (@rowsToCalculate > 0) BEGIN 
    INSERT INTO @result (MovieID int, Distance int) 
    SELECT TOP(@rowsToCalculate) 
     movieID 
    , dbo.MovieEuclideanDistance(@movieID,m.movieID) AS distance 
    FROM 
    dbo.Movies 
    WHERE 
    movieID != @movieID 
    AND dbo.CompareMovieHashes(@movieID, MovieID) = 1 
    AND (CoordX != @currentX OR CoordY != @currentY) 
    ORDER BY 
    Distance 
END