List the names of the coins above the average price on April 28, 2013.
average price = divide(sum(price), count(name)); on April 28, 2013 refers to date = '2013-04-28'
SELECT T1.name FROM coins AS T1 INNER JOIN historical AS T2 ON T1.id = T2.coin_id WHERE T2.date = '2018-04-28' AND T2.price > ( SELECT AVG(price) FROM historical WHERE date = '2018-04-28' )
CREATE TABLE coins
(
    id            INTEGER not null
        primary key,
    name          TEXT,
    slug          TEXT,
    symbol        TEXT,
    status        TEXT,
    category      TEXT,
    description   TEXT,
    subreddit     TEXT,
    notice        TEXT,
    tags          TEXT,
    tag_names     TEXT,
    website       TEXT,
    platform_id   INTEGER,
    date_added    TEXT,
    date_launched TEXT
);
CREATE TABLE IF NOT EXISTS "historical"
(
    date               DATE,
    coin_id            INTEGER,
    cmc_rank           INTEGER,
    market_cap         REAL,
    price              REAL,
    open               REAL,
    high               REAL,
    low                REAL,
    close              REAL,
    time_high          TEXT,
    time_low           TEXT,
    volume_24h         REAL,
    percent_change_1h  REAL,
    percent_change_24h REAL,
    percent_change_7d  REAL,
    circulating_supply REAL,
    total_supply       REAL,
    max_supply         REAL,
    num_market_pairs   INTEGER
);
