Mykeal Kenny

queries.sql

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+-- Pretty formatting
+.mode column
+.header on
+
+-- Creates a persistent DB for my chat system
+.open chat.db
+
+-- * Users TABLE (e.g. `Dave`)
+-- ID, NAME,
+CREATE TABLE user (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    name VARCHAR(255) NOT NULL UNIQUE
+);
+-- * Organizations TABLE (e.g. `Lambda School`)
+-- ID, NAME,
+CREATE TABLE organization (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    name VARCHAR(255) NOT NULL UNIQUE
+);
+-- * Channels TABLE (e.g. `#random`)
+-- ID, NAME, ORGANIZATION_ID
+CREATE TABLE channel (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    name VARCHAR(255) NOT NULL UNIQUE,
+    organization_id INTEGER REFERENCES organization(id)
+);
+-- * Messge TABLE ()
+-- ID, POST_TIME, CONTENT, AUTHOR, CHANNEL
+CREATE TABLE messages (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    post_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    content LONGTEXT, 
+    user_id INTEGER REFERENCES user(id),
+    channel_id INTEGER REFERENCES channel(id)
+);
+-- * CHANNEL_SUBSCRIPTIONS
+-- CHANNEL_ID, USER_ID
+CREATE TABLE channel_sub (
+    channel_id INTEGER REFERENCES channel(id),
+    user_id INTEGER REFERENCES user(id)
+);
+-- #### INSERT LAND ######## --
+--   1. One organization, `Lambda School`
+INSERT INTO organization (name) VALUES ('Lambda School');
+--   2. Three users, `Alice`, `Bob`, and `Chris`
+INSERT INTO user(name)VALUES('Alice');
+INSERT INTO user(name)VALUES('Bob');
+INSERT INTO user(name)VALUES('Chris');
+
+--   3. Two channels, `#general` and `#random`
+INSERT INTO channel(name,organization_id)VALUES('#general', 1);
+INSERT INTO channel(name,organization_id)VALUES('#random', 1);
+
+
+--   5. `Alice` should be in `#general` and `#random`.
+INSERT INTO channel_sub (channel_id, user_id)VALUES(1,1);
+INSERT INTO channel_sub (channel_id, user_id)VALUES(2,1); 
+
+--   6. `Bob` should be in `#general`.
+INSERT INTO channel_sub (channel_id, user_id)VALUES(1,2);
+
+--   7. `Chris` should be in `#random`.
+INSERT INTO channel_sub (channel_id, user_id)VALUES(2,3);
+
+--   4. 10 messages (at least one per user, and at least one per channel).
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Alice in #general',
+    1,1
+);
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Alice in #random',
+    2,1
+);
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Alice in #random',
+    2,1
+);
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Bob in #general',
+    2,1
+);
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Chris in #general',
+    3,1
+);
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Alice in #general',
+    1,1
+);
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Bob in #general',
+    2,1
+);
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Chris in #general',
+    3,1
+);
+
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Bob in #general',
+    2,1
+);
+INSERT INTO messages (content, user_id, channel_id)VALUES(
+    'This is a message from Bob in #general',
+    2,1
+);
+
+-- #### QUERY LAND ######## --
+-- 1. List all organization `name`s.
+SELECT name AS Organizaton_name FROM organization;
+
+-- 2. List all channel `name`s.
+SELECT name AS Channel_name FROM channel;
+
+-- 3. List all channels in a specific organization by organization `name`.
+SELECT name AS LS_Channel FROM channel WHERE organization_id IS (SELECT id FROM organization WHERE name IS 'Lambda School');
+
+-- 4. List all messages in a specific channel by channel `name` `#general` in
+-- order of `post_time`, descending.
+SELECT * FROM messages WHERE channel_id IS (SELECT id FROM channel WHERE name IS '#general') ORDER BY post_time DESC;
+
+-- 5. List all channels to which user `Alice` belongs.
+SELECT c.name AS Alice_Channels, c.id AS Channel_ID  FROM channel AS c INNER JOIN channel_sub AS cs ON c.id IS cs.channel_id INNER JOIN user AS u ON u.id IS cs.user_id WHERE u.name IS 'Alice';
+
+-- 6. List all users that belong to channel `#general`.
+SELECT u.name AS UsersInGeneral FROM user AS u INNER JOIN channel_sub AS cs ON u.id IS cs.user_id INNER JOIN channel AS c ON cs.channel_id IS c.id WHERE c.name IS "#general";
+-- 7. List all messages in all channels by user `Alice`.
+SELECT post_time AS Posted_AT, content AS Body_Message, u.name AS USERNAME FROM messages AS m INNER JOIN user AS u ON user_id IS u.id WHERE u.name IS 'Alice';
+-- 8. List all messages in `#random` by user `Bob`.
+SELECT * FROM messages WHERE channel_id IS (SELECT id FROM channel WHERE name IS '#random');
+-- 9. List the count of messages across all channels per user. (Hint:
+-- `COUNT`, `GROUP BY`.)
+SELECT COUNT (u.id) AS 'Message Count Totals', u.name AS 'Username' FROM messages AS m INNER JOIN user AS u on m.user_id IS u.id INNER JOIN channel AS c WHERE m.channel_id IS c.id GROUP BY u.id;
+-- The title of the user's name column should be `User Name` and the title of
+-- the count column should be `Message Count`. (The SQLite commands
+-- `.mode column` and `.header on` might be useful here.)
+
+-- DROP TABLE  organization;
+-- DROP TABLE  channel;
+-- DROP TABLE  user;
+-- DROP TABLE  messages;
+-- DROP TABLE  channel_sub;
+
+-- 6. What SQL keywords or concept would you use if you wanted to automatically
+--    delete all messages by a user if that user were deleted from the `user`
+--    table?
+
+-- I would us ON DELETE CASCADE and use it to specify it in the Foreign Key Constraint in the schema for my messages.