Question

这些是表格信息。

CREATE TABLE actor(
id INTEGER NOT NULL,
name VARCHAR2(100),
CONSTRAINT actor_PK PRIMARY KEY (id));

CREATE TABLE movie(
id INTEGER NOT NULL,
title VARCHAR2(100),
yr NUMBER(4,0),
score NUMBER,
votes INTEGER,
director VARCHAR2(100),
CONSTRAINT movie_PK PRIMARY KEY (id));

CREATE TABLE casting(
movie_id INTEGER NOT NULL,
actor_id INTEGER NOT NULL,
ord INTEGER,
CONSTRAINT casting_PK PRIMARY KEY (movie_id, actor_id),
CONSTRAINT casting_FK1 FOREIGN KEY (movie_id) REFERENCES movie(id),
CONSTRAINT casting_FK2 FOREIGN KEY (actor_id) REFERENCES actor(id));

我如何找到用作电影标题中第一个单词的前5个热门单词？（不包括“ A”，“ An”，“ The”和“ I”）。按从高到低的顺序列出单词。您可以忽略只有一个单词的电影标题。

Answer 1

此简单方法将查找第一次出现的空白（仅在带有空白的标题中）。它将按丢弃列表的出现次数降序排列（“ A”，“ An”，“ The”，“ I”）

with words AS (
    SELECT
        substr(m.title, 1, instr(m.title, ' ')) AS firstword,
        COUNT(*) AS counter
    FROM
        movie m
    WHERE
        instr(m.title, ' ') > 0
    GROUP BY
        substr(m.title, 1, instr(m.title, ' '))
)
SELECT
    w.firstword,
    w.counter
FROM
    words w
where UPPER(w.firstword) not in ('A', 'AN', 'THE', 'I')
ORDER BY
    w.counter DESC

如果不区分大小写：

with words AS (
    SELECT
        UPPER(substr(m.title, 1, instr(m.title, ' '))) AS firstword,
        COUNT(*) AS counter
    FROM
        movie m
    WHERE
        instr(m.title, ' ') > 0
    GROUP BY
        UPPER(substr(m.title, 1, instr(m.title, ' ')))
)
SELECT
    w.firstword,
    w.counter
FROM
    words w
where w.firstword not in ('A', 'AN', 'THE', 'I')
ORDER BY
    w.counter DESC

如何在SQL中查找重复的单词？

1 个答案: