IN
SELECT count(*) FROM world.country where Name IN (SELECT Name FROM world.country where Name like "C%");
匹配子集中的任一元素
NOT IN
SELECT count(*) FROM world.country where Name NOT IN (SELECT Name FROM world.country where Name like "C%");
匹配不属于某个子集的任一元素
ALL
SELECT count(*) FROM world.country WHERE Name<>all(SELECT Name FROM world.country where Name like "C%");
与子集中的每一个元素
比如:
val>ALL(subset):表示val比subset中每一个元素都大
val<>ALL(subset):表示val不在subset中,等效于NOT IN (subset)
ANY,SOME
SELECT count(*) FROM world.country WHERE Name=any(SELECT Name FROM world.country where Name like "C%");
ANY表示任一个,SOME是ANY的变体,含义相同
比如:
val=ANY(subset):表示val等于subnet子集中的任何一个元素皆可,等同于val IN (subnet)
val>ANY(subnet):表示val比subnet中最小的元素大即可