SQL Server - 如果存在于其他表中，则更改列？

Question

Playing around with SQL Server 2008 and I have a table People with columns:

Name  | City |  Born | ...

and another table Change with columns:

OldName  |  NewName

Now I would like to change Name in the table People something like this: if there is the same OldName in table Change as the Name in People then change the Name in People to the NewName in Change .

Any easy way?

Oh and another question to this: if the Name in People would be the primary key (or let say Name and City would be composite key), would it be much harder to change the name? Thx

Answer 1

Answer1)

UPDATE people,change
SET people.name = change.newname
WHERE people.name = change.oldName

EDIT with inner Join syntax:

UPDATE people
SET people.name = change.newName
FROM people
INNER JOIN change ON people.name = change.oldName

I don't have a SQL Server to test that on, but based on online examples, it should work.

/Edit

Answer2) As long as you still maintain uniqueness in the key it wouldn't be difficult to change at all. As soon as you cause a collision you would get an error. For this reason it would be best to have an auto-incrementing ID field in people that would be your PK

Answer 2

You might be better off to add a PeopleId column to the People table, and replace the OldName column in the Change table with a PeopleId column that has a foreign key relationship back to the People table:

People:

PeopleId | Name   | City     | Born
-------------------------------------------
1        | Fred   | New York | 1/1/1980
2        | Wilma  | Boston   | 1/1/1980

Change:

PeopleId | NewName
----------------------
1        | Barney