-- #####################################################
-- [ ADD DATA TO DB ]

-- SELECT DATABASE
USE mydb;

-- GET USER ID
SELECT @userID := 1408;

-- ADD USER
INSERT INTO users (user_id, name)
    VALUES (@userID, 'Vasia');

-- ADD QUESTION
INSERT INTO questions (text)
    VALUES ('Ты охуел?');

-- GET QUESTION ID
SELECT @questionID := LAST_INSERT_ID();

-- INSERT ANSWER
INSERT INTO answers (text)
    VALUE ('Да.');

-- GET ANSWER ID
SELECT @answerID := LAST_INSERT_ID();

-- LINK THE QUESTION AND THE ANSWER
INSERT INTO conn_quest_ans (question_id, answer_id, user_id)
    VALUES (@questionID, @answerID, @userID);

-- ############################################################
-- [ GET DATA FROM DB ]

-- GET USER ID
SELECT @userID := 1408;

-- GET USER'S COINS AND EXP
SELECT @user_coins := coins, @user_exp := exp FROM users
    WHERE user_id = @userID;

-- INCREMENT COINS AND EXP
UPDATE users SET coins = @user_coins + 1, exp = @user_exp + 1
    WHERE user_id = @userID;

-- SEARCH THE QUESTION
-- TRY REGEXP NEXT TIME !!!
SELECT @questionID := question_id FROM questions
    WHERE text = 'Ты охуел?';

-- GET ALL RELATED ANSWERS' IDs
SELECT @answID := answer_id, @relatedUserID := user_id FROM conn_quest_ans
    WHERE question_id IN (@questionID);

-- GET ALL ANDSWERS
SELECT text FROM answers
    WHERE answer_id = @answID

-- @relatedUserID might be used to choose the best answer