Update a thousand rows with specific value

I would like to update thousand of Rows with its specific value

Suppose i have a table XYZ and ABC
XYZ contains Code,Name,RegDate And ABC also Contains the same
but the Value of RegDate of XYZ is Different than that of ABC..
i want to update XYZ's RegDate Value From the value of RegDate of table ABC
at once...

update XYZ set RegDate=

How are the two tables related? What's the key that link them together?

Happy Coding!!!

~~ CK

One of the simplest ways is
but as ck says, you don't indicate which fields are the key

Small modification in the posted SQL

UPDATE xyx
set datereg=
(
select datereg from abc
where abc.Code=xyz.code
and abc.name=xyz.Name
and abc.datereg <> xyz.datereg
)

Yet another version :)

Happy Coding!!!

~~ CK

Update a set a.regdate=b.regdate from xyz a,abc b
where a.code=b.code and a.name=b.name and a.regdate<>b.regdate