Sql 两个更新查询

为了更新列，我尝试了两个查询

更新查询1：

DECLARE @Counter INT=0 --This causes the @@rowcount to be > 0

while @@rowcount>0
begin
   set rowcount 10000

   update r
   set Comp = t.Comp
   from [dbo].[Vente] r 
   inner join [dbo].tempBudgeT t with (index (index_Budget )) 
                 on t.[Code Site] = r.[Code Site]
                 and t.[Code Structure] = r.[Code Structure]
                 and t.[Date Time] = convert(date, r.[Date Time])
   where r.[Date Time] >= '2015-01-01 00:0:00.000'
     and r.Comp is null
end

SET rowcount 0 

更新查询2：

 DECLARE @Counter INT=0 --This causes the @@rowcount to be > 0

 while @@rowcount > 0
 begin
     set rowcount 10000

     update [dbo].[Vente] 
     set Comp = (select top 1 t.comp
                 from [dbo].[Budget] t with (index (index_Budget))
                 where t.[Code Site] = [dbo].[Vente].[Code Site]
                   and t.[Code Rayon] = substring([dbo].[Vente].[Code Structure], 1, 4)
                   and t.[Date Time] = convert(date, [dbo].[Vente].[Date Time])
                   and [dbo].[Vente].[Date Time] >= '2015-01-01 00:0:00.000'
                   and [dbo].[Vente].Comp is null)
 end

 SET rowcount 0 

我的问题是第二个查询比第一个查询快，但它不起作用，comp没有用第二个查询更新吗？问题出在哪里？

您的[dbo].[Vente]和[dbo].[Budget]尚未加入，请在subquery中更新条件：

DECLARE @Counter INT = 0 --This causes the @@rowcount to be > 0

WHILE @@rowcount > 0
BEGIN
    SET ROWCOUNT 10000

    UPDATE v
    SET Comp = (
            SELECT TOP 1 t.comp
            FROM [dbo].[Vente] v
            INNER JOIN [dbo].[Budget] t WITH (INDEX (index_Budget)) t.[Code Site] = v.[Code Site]
            WHERE t.[Code Site] = v.[Code Site]
                AND t.[Code Rayon] = substring([dbo].[Vente].[Code Structure], 1, 4)
                AND t.[Date Time] = convert(DATE, [dbo].[Vente].[Date Time])
                AND [dbo].[Vente].[Date Time] >= '2015-01-01 00:0:00.000'
                AND [dbo].[Vente].Comp IS NULL
            )
END

SET ROWCOUNT 0

---

通过将更新更改为select并查看返回的内容来进行故障排除。如果没什么，开始一个接一个地移除过滤器，直到有东西返回。一旦您确定了字段，请选择它并将实际结果与您期望的结果进行比较。因为第二个查询是错误的，@Backs查询似乎还可以，但我认为它并不比第一个查询好。现在在第一个查询中，我不明白为什么要使用while循环和rowCount。当它只循环一次时。您真正的问题是什么。