SQL 2008, Update using multiple SubQuery

Question

Hello Experts , 
I WANT TO DO THIS UPDATE WITHOUT USING CTE
I have Two Table  REGION and AREA 
REGION TABLE HAVE VALUE LIKE 
Create Table REGIONtbl (REGION varchar(20),SomeArea varchar(20))
Insert into REGIONtbl
select 'REGION1','' union all
select 'REGION2','' union all
select 'REGION3','' 
select *  from REGION
OTHER table is AREA
Create Table AREAtbl(AREAS  varchar(20))
Insert into Areatbl
select 'area1','' union all
select 'area2','' union all
select 'area3','' 
I want to upadte AREAs in SomeArea column of Region Table ,
I Need to first create autoincrement column in both Table using Row_Number function  and Upadte "SOMEAREA" column with "Areas" column 
where ever ROW_Number ID of both the Table match 
I tried below but did not work..
UPDATE MASTER 
SET MASTER.somearea =ar.areas
FROM 
SELECT Row_number() over (order by REGION) RN,
REGION, somearea FROM REGIONtbl
) AS MASTER
SELECT areas, ROW_NUMBER() OVER (ORDER BY areas)RNa
FROM areatbl
)AR
where MASTER.rn=ar.rna
HELP ?

Answer 1

Please post DDL, so that people do not have to guess what the keys, constraints, Declarative Referential Integrity, data types, etc. in your schema are. Learn how to follow ISO-11179 data element naming conventions and formatting rules. You have no idea.
Temporal data should use ISO-8601 formats. Code should be in Standard SQL as much as possible and not local dialect. 
This is minimal polite behavior on SQL forums. 
>> I want to do this update without using CTE <<
Why? Is that part of a homework assignment? 
>> I have Two Tables REGION [sic] and AREA [sic] <<
No, tables are sets so their names plural or collective nouns. Putting “tbl” in a name is called “tibble”, a common design flaw that we laugh at. Look for Phil Factor’s humor column on this. 
Here is my guess at what you should have posted in order to do this the way you want to do it.
CREATE SEQUENCE Region_Garbage
AS INTEGER 
START WITH 1 
INCREMENT BY 1;
CREATE SEQUENCE Area_Garbage
AS INTEGER 
START WITH 1 
INCREMENT BY 1;
CREATE TABLE Regions
(region_name VARCHAR(20) NOT NULL PRIMARY KEY, 
 region_seq INTEGER NOT NULL,
 area_name VARCHAR(20) DEFAULT '' NOT NULL);
INSERT INTO Regions (region_name, region_seq) 
VALUES ('region_name1', NEXT VALUE FOR Region_Garbage);
INSERT INTO Regions (region_name, region_seq) 
VALUES ('region_name2', NEXT VALUE FOR Region_Garbage);
INSERT INTO Regions (region_name, region_seq) 
VALUES ('region_name3', NEXT VALUE FOR Region_Garbage);
CREATE TABLE Areas
(area_name VARCHAR(20) NOT NULL PRIMARY KEY,
 area_seq INTEGER NOT NULL);
INSERT INTO Areas (area_name, area_seq) 
VALUES ('area_name1', NEXT VALUE FOR area_Garbage);
INSERT INTO Areas (area_name, area_seq) 
VALUES ('area_name2', NEXT VALUE FOR area_Garbage);
INSERT INTO Areas (area_name, area_seq) 
VALUES ('area_name3', NEXT VALUE FOR area_Garbage);
CREATE TABLE Areas
(area_name VARCHAR(20) NOT NULL PRIMARY KEY,
 area_seq NEXT VALUE FOR Area_Garbage);
>> I want to update area_name column of Regions Table <<
I would fire you for doing this, but here is a stinking kludge.
The term “Master” is from magnetic tape files, not RDBMS! Then to make it worse, you have used the old Sybase UPDATE. FROM.. syntax! It is unpredictable. Use the MERGE: 
MERGE INTO Regions AS R
USING Areas AS X
ON X.area_seq = R.region_seq 
WHEN MATCHED
THEN UPDATE
     SET area_name = X.area_name;
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