[Postgres] Filter Data in a Postgres Table with Query Statements

We have all this data, but how do we answer questions about it? In this lesson we’ll learn how to filter down to just the information we’re looking for.

SELECT title
FROM movies;

SELECT title
FROM movies
WHERE release_date > '01-01-1975';

SELECT title,
release_date
FROM movies
WHERE release_date > '01-01-1975';

SELECT *
FROM movies
WHERE count_stars=5;

SELECT title AS name
FROM movies;

SELECT *
FROM movies
WHERE count_stars < 5;

SELECT *
FROM movies
WHERE release_date > '01-01-1975';

SELECT COUNT(*)
FROM movies
WHERE release_date > '01-01-1975';

SELECT AVG(count_stars)
FROM movies
WHERE release_date > '01-01-1975';

SELECT SUM(count_stars)
FROM movies;

SELECT title,
count_stars,
((count_stars::float / 5) * 100) AS rotten_tomatoes_score
FROM movies
WHERE release_date > '01-01-1975';

SELECT * FROM movies 
WHERE release_date > '10-10-2013'
AND
count_stars > 4
原文地址:https://www.cnblogs.com/Answer1215/p/6516420.html