对表中的每一行运行 SQL Server 函数

Question

我有一个函数，它在表中“针对每一行”进行迭代。当它运行时，它应该查看每一行，为该行提取相关的 SET 值并运行该函数，该函数依次返回结果并使用正确的值更新正确的行。正在发生的事情是它正在运行并返回最后一行的值并使用该值更新所有行。任何想法我做错了什么？

SELECT 
     RowNum = ROW_NUMBER() OVER(ORDER BY ID)
     ,*
INTO #Geo
FROM DDDG

DECLARE @MaxRownum INT
SET @MaxRownum = (SELECT MAX(RowNum) FROM #Geo)

DECLARE @Iter INT
SET @Iter = (SELECT MIN(RowNum) FROM #Geo)

WHILE @Iter <= @MaxRownum
BEGIN
     SELECT *
     FROM #Geo
     WHERE RowNum = @Iter

    DECLARE @address nvarchar (100);
    Select @address =  Ad1 from DDDG where id = @Iter;

    DECLARE @state nvarchar (100);
    SET @state = 'FL';

    DECLARE @zip nvarchar (100);
    SET @zip = '33142';

    DECLARE @city nvarchar (100);
    SET @city = 'Miami';

    DECLARE @nation nvarchar (2);
    SET @nation = 'us';

    DECLARE @g geography;

    WAITFOR DELAY '00:00:00.050'
    SET @g = dbo.Geocode(@nation, @state, @city, @zip, @address);

    Update DDDG 
    Set Lat = @g.Lat 
    where id = @Iter;

    Update DDDG 
    Set long = @g.Long 
    where id = @Iter;

     SET @Iter = @Iter + 1
END

DROP TABLE #Geo

更新.....

谢谢大家......我几乎让它工作了......经过大量的试验和错误后，我发现我需要更改以下内容

Update DDDG Set Lat = @g.Lat where id = id;
Update DDDG Set long = @g.Long where id = id;

我现在只有一个问题。当我删除行时，RowNum 和 @Iter 不再匹配。除了每次都重新创建表格之外，有没有办法解决这个问题？

Answer 1

我可能遗漏了一些东西，但你为什么需要一个循环呢？：

UPDATE DDDG
SET Lat     = dbo.GeoCode('us','FL','Miami','33142',Ad1).Lat,
    Long    = dbo.GeoCode('us','FL','Miami','33142',Ad1).Long;

还可以通过将dbo.GeoCode 的调用次数减少到每行一个来进一步改进查询：

UPDATE t
SET Lat     = g.GC.Lat,
    Long    = g.GC.Long
FROM DDDG AS t
CROSS APPLY (
    SELECT dbo.GeoCode('us','FL','Miami','33142',Ad1) AS GC
) AS g;

Answer 2

WITH CTE_DDD(ID,Ad1)
AS
(
  SELECT ID, Ad1 FROM DDD
)
UPDATE d 
SET d.lat = dbo.Geocode(@nation, @state, @city, @zip,Ad1).lat, long = dbo.Geocode(@nation, @state, @city, @zip,Ad1).long 
FROM DDD d 
WHERE d.id = ID

在收到同行对上述问题的反对票后修改查询：

WITH CTE_DDD AS
(
  SELECT * FROM DDD
)
UPDATE CTE_DDD SET lat = (SELECT lat from dbo.Geocode(@nation, @state, @city, @zip,Ad)), long = (SELECT long from    dbo.Geocode(@nation, @state, @city, @zip,Ad))

我同意 CROSS APPLY 是一个更好的解决方案，因为它每行调用一次函数。