SQL - Create view from multiple tables

Question

I have three tables:

POP(country, year, pop)
FOOD(country, year, food)
INCOME(country, year, income)

I am trying to create a view such as:<

Answer 1

Are you using MySQL or PostgreSQL?

You want to use JOIN syntax, not UNION. For example, using INNER JOIN:

CREATE VIEW V AS
SELECT POP.country, POP.year, POP.pop, FOOD.food, INCOME.income
FROM POP
INNER JOIN FOOD ON (POP.country=FOOD.country) AND (POP.year=FOOD.year)
INNER JOIN INCOME ON (POP.country=INCOME.country) AND (POP.year=INCOME.year)

However, this will only show results when each country and year are present in all three tables. If this is not what you want, look into left outer joins (using the same link above).