1046.MovieEx-Find the names of all reviewers who have contributed three or more ratings
题目描述
Find the names(name)
of all reviewers who have contributed three or more ratings. (As an extra
challenge, try writing the query without HAVING or without COUNT.)
You can find the full
data description here
movie ( mID, title, year,
director )
English: There is a movie with ID number mID,
a title, a release year, and a director.
mID |
title |
year |
director |
int |
varchar |
int |
varchar |
101 |
Gone with the Wind |
1939 |
Victor Fleming |
102 |
Star Wars |
1977 |
George Lucas |
reviewer ( rID, name )
English: The reviewer with ID number rID
has a certain name.
rID |
name |
int |
varchar |
201 |
Sarah Martinez |
202 |
Daniel Lewis |
rating ( rID, mID, stars,
ratingDate )
English: The reviewer rID gave the
movie mID a number of stars rating (1-5) on a certain ratingDate.
rID |
mID |
stars |
ratingDate |
int |
int |
int |
date |
201 |
101 |
2 |
2011-01-22 |