sql - 编写引用嵌套 VARRAY 的 SQL 语句

Question

我正在尝试编写一个 SQL 语句，该语句在不使用 PL/SQL 的情况下查询名为的表中的列actors（定义为VARRAY(5)）movie，以回答以下问题：

列出出现在多部电影中的任何演员，显示电影名称和演员

select a.column_value, count(*), m.title
from movie m, table (m.actors) a
where count(*) > 2,
group by a.column_value;

Answer 1

您应该使用该HAVING子句而不是 where 子句来检查条件，并且还LISTAGG可以用于显示电影标题。

CREATE OR REPLACE TYPE actortype IS VARRAY(5) OF VARCHAR2(20);
/

create table movie ( id integer , title VARCHAR2(100), actors actortype );

INSERT INTO movie (
     id,
     title,
     actors
) VALUES (
     1,
     'The Shawshank Redemption',
     actortype('Morgan Freeman','Tim Robbins','Bob Gunton')
);
INSERT INTO movie (
     id,
     title,
     actors
) VALUES (
     1,
     'The Dark Knight',
     actortype('Morgan Freeman','Christian Bale','Heath Ledger')
);

询问

SELECT a.column_value as Actor,
       COUNT(*) as num_of_movies,
       LISTAGG( m.title, ',') WITHIN GROUP ( ORDER BY id ) as movies
FROM movie m,
     TABLE ( m.actors ) a
GROUP BY a.column_value
HAVING COUNT(*) > 1;

ACTOR          NUM_OF_MOVIES MOVIES
------------  -------------  -------
Morgan Freeman  2            The Dark Knight,The Shawshank Redemption