Views

A view is a virtual table based on the result set of a SQL statement. It derives its fields from a SELECT statement. You can do anything with a MapD view query that you can do in a non-view MapD query.

CREATE VIEW

Creates a view based on a SQL statement.

CREATE VIEW <view_name> AS <sql_statement>;

Example:

CREATE VIEW view_movies
AS SELECT movies.movieId, movies.title, movies.genres, avg(ratings.rating)
FROM ratings
JOIN movies on ratings.movieId=movies.movieId
GROUP BY movies.title, movies.movieId, movies.genres;

You can describe the view as you would a table.

\d view_movies
View defined as: select  movies.movieId, movies.title, movies.genres,
avg(ratings.rating) from ratings JOIN movies on ratings.movieId=movies.movieId
group by movies.title, movies.movieId, movies.genres
Column types:
    movieId INTEGER,
    title TEXT ENCODING DICT(32),
    genres TEXT ENCODING DICT(32),
    EXPR$3 DOUBLE

You can query the view as you would a table.

SELECT title, EXPR$3 from view_movies where movieId=260;
Star Wars: Episode IV - A New Hope (1977)|4.048937

DROP VIEW

Removes a view created by the CREATE VIEW statement. The view definition is removed from the database schema, but no actual data in the underlying base tables is modified

DROP VIEW [IF EXISTS] <view>;

Example:

DROP VIEW IF EXISTS v_reviews;