SELECT Name, Population, SurfaceArea
FROM country
WHERE Population > 200000000
UNION
SELECT Name, Population, SurfaceArea
FROM country
WHERE SurfaceArea > 9000000
| Name |
Population |
SurfaceArea |
| China |
1,277,558,000 |
9,572,900.00 |
| Indonesia |
212,107,000 |
1,904,569.00 |
| India |
1,013,662,000 |
3,287,263.00 |
| United States |
278,357,000 |
9,363,520.00 |
| Antarctica |
0 |
13,120,000.00 |
| Canada |
31,147,000 |
9,970,610.00 |
| Russian Federation |
146,934,000 |
17,075,400.00 |
| 该语句由 UNION 关键字分开的两条 SELECT 组成，两条语句的字段数量和类型相同。UNION 让数据库执行两条 SELECT，并把结果合并成一个结果集。
UNION 会自动去掉结果集中的重复行。 |