问题从旧表迁移到新表

时间:2018-11-13 23:52:52

标签: sql sql-server sql-server-2005 sql-server-2012

我正在将数据从一个表转移到另一个表。

旧表曾经有一个名为City的varchar列。

新表(而不是城市名称)具有一个名为CityId的int列,因为我仅为城市创建了新表。

“我的城市”表具有以下列:

CityID - PK

RegionID - FK

CityName - Varchar(50)

我正在运行此查询以复制新表的旧数据:

INSERT INTO dbo.Client(EmailAddress, CityID)
a.EmailAddress, (SELECT CityID FROM Cities WHERE CityName collate SQL_Latin1_General_CP1_CI_AS = a.City)
FROM AdventureWorksOld.dbo.Client a

但是我不能这样做,因为子查询返回多行:

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

如何修复我的代码,以便可以执行以下操作:

SELECT (SELECT CityName FROM Cities WHERE CityName = 'Oak Bay') -> Replace 'Oak Bay' with the text in the column
FROM AdventureWorksOld.dbo.Client

谢谢。

2 个答案:

答案 0 :(得分:-1)

这可能是您在寻找什么?

INSERT INTO dbo.Client(EmailAddress, CityID)
SELECT 
    a.EmailAddress
,   c.CityID 
FROM AdventureWorksOld.dbo.Client a
LEFT JOIN Cities c ON c.CityName = a.City 

答案 1 :(得分:-1)

尝试一下:

INSERT INTO dbo.Client(EmailAddress, CityID)
SELECT 
    a.EmailAddress
,   c.CityID 
FROM AdventureWorksOld.dbo.Client a
OUTER APPLY (SELECT TOP 1 c.CityID FROM Cities c WHERE c.CityName = a.City) c