Same SQL Query in 4 different ways

1. With Sub Query
SELECT Name, Region FROM bbc
WHERE Region In(
SELECT Region FROM bbc WHERE Name=’India’ OR Name=’Iran’)
2. With Exists clause
SELECT Name, Region FROM bbc b
WHERE EXISTS(SELECT Region FROM bbc WHERE Region = b.Region
AND (Name=’India’ OR Name=’Iran’))
3. With Old style joins
SELECT b.Name, b.Region FROM bbc b, bbc c
WHERE b.Region = c.Region
AND ((c.Name=’India’) OR (c.Name=’Iran’))
4. With ANSI Joins
SELECT b.Name, b.Region FROM bbc b
INNER JOIN bbc c
ON b.Region = c.Region
AND ((c.Name=’India’) OR (c.Name=’Iran’))