Question

我有两张桌子：

1.
CREATE TABLE [dbo].[HotelSourceMap](
[hotelsourcemapid] [bigint] IDENTITY(1,1) NOT NULL,
[dspartnerid] [bigint] NOT NULL,
[dshotelid] [bigint] NOT NULL,  
[countrycode] [varchar](5) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[countryid] [bigint] NULL)

2.
CREATE TABLE [dbo].[country](
[countryId] [smallint] IDENTITY(1,1) NOT NULL,
[countryName] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
[countryCode] [varchar](2) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL)

情况是这样的：我想从country.countryid更新HotelSourceMap表中的countryid。其中hotelsourcemap.countrycode = country.countrycode

有些事情是这样的：

UPDATE HotelSourceMap
SET
HotelSourceMap.countryid =country.countryId  
WHERE
HotelSourceMap.countrycode = country.countryCode

Answer 1

可能有一个基于集合的解决方案，在这种情况下，这将是更好的，我相信有人会发布它，但在那之前，至少这将完成这项工作：

UPDATE
    HotelSourceMap
SET
    countryid = (SELECT countryId FROM country WHERE country.countryCode = HotelSourceMap.countrycode)

Answer 2

这是一个值得怀疑的表设计，但这里是SQL：

UPDATE    HotelSourceMap
SET       countryid = co.countryId
FROM      HotelSourceMap AS hsm
    JOIN  country        AS co
        ON (hsm.countryCode = co.countryCode)

请告诉我如何为这样的问题创建更新查询

2 个答案: