Question

UPDATE main
SET main.PCH_2YR =
(SELECT TOP 1 sub.PCH_2YR FROM [dbGlobalPricingMatrix].[dbo].[tblPCHLookup_Test] sub WHERE
sub.capid = main.capid AND
sub.milespa = main.mileage AND
sub.maintained = main.maintenance AND sub.pch_2yr IS NOT NULL)
FROM [dbWebsiteLO3-PRICING]..Vehicles_Staging_Data main

如果子查询返回的值不是NULL，我只想设置值。我怎么能这样做？

只有一行符合条件，但我只想使用它的值，如果它不是NULL。

Answer 1

尝试如下查询：

UPDATE main
SET main.PCH_2YR =sub.PCH_2YR
FROM [dbWebsiteLO3-PRICING]..Vehicles_Staging_Data main LEFT JOIN
[dbGlobalPricingMatrix].[dbo].[tblPCHLookup_Test] sub ON 
sub.capid = main.capid AND
sub.milespa = main.mileage AND
sub.maintained = main.maintenance AND sub.pch_2yr IS NOT NULL
WHERE sub.PCH_2YR is NOT NULL

Answer 2

您可以在桌面上执行INNER JOIN而不是子查询。 INNER JOIN过滤掉另一个表中没有匹配项的记录。

UPDATE main
SET main.PCH_2YR = sub.PCH_2YR
FROM [dbWebsiteLO3-PRICING]..Vehicles_Staging_Data main
INNER JOIN [dbGlobalPricingMatrix].[dbo].[tblPCHLookup_Test] sub 
        ON sub.capid = main.capid 
        AND sub.milespa = main.mileage 
        AND sub.maintained = main.maintenance 
        AND sub.pch_2yr IS NOT NULL

仅在非null时才更新SQL

2 个答案: