7. 小案例

-- 建库建表
-- 如果数据库已存在就删除
drop database if exists db_msg cascade ;
-- 创建数据库
create database db_msg ;
-- 切换数据库
use db_msg ;
-- 列举数据库
show databases ;

-- 如果表已存在就删除
drop table if exists db_msg.tb_msg_source ;
-- 建表
create table db_msg.tb_msg_source(
msg_time string comment "消息发送时间",
sender_name string comment "发送人昵称",
sender_account string comment "发送人账号",
sender_sex string comment "发送人性别",
sender_ip string comment "发送人ip地址",
sender_os string comment "发送人操作系统",
sender_phonetype string comment "发送人手机型号",
sender_network string comment "发送人网络类型",
sender_gps string comment "发送人的GPS定位",
receiver_name string comment "接收人昵称",
receiver_ip string comment "接收人IP",
receiver_account string comment "接收人账号",
receiver_os string comment "接收人操作系统",
receiver_phonetype string comment "接收人手机型号",
receiver_network string comment "接收人网络类型",
receiver_gps string comment "接收人的GPS定位",
receiver_sex string comment "接收人性别",
msg_type string comment "消息类型",
distance string comment "双方距离",
message string comment "消息内容"
);

-- 加载数据
-- 上传文件到Linux系统
-- load数据到表
load data local inpath '/home/hadoop/chat_data-30W.csv' overwrite into table tb_msg_source;

-- 验证数据
SELECT * FROM tb_msg_source limit 10;
SELECT * FROM tb_msg_source TABLESAMPLE(100 ROWS);

-- ETL数据清洗
-- ETL：
-- E，Extract，抽取
-- T，Transform，转换
-- L，Load，加载
-- 从A抽取数据(E)，进行数据转换过滤(T)，将结果加载到B(L)，就是ETL啦

-- 数据问题 
-- 问题1：当前数据中，有一些数据的字段为空，不是合法数据
select
   msg_time,
   sender_name,
   sender_gps
from db_msg.tb_msg_source
where length(sender_gps) = 0
limit 10;

-- 问题2：需求中，需要统计每天、每个小时的消息量，但是数据中没有天和小时字段，只有整体时间字段，不好处理
select
   msg_time
from db_msg.tb_msg_source
limit 10;

-- 问题3：需求中，需要对经度和维度构建地区的可视化地图，但是数据中GPS经纬度为一个字段，不好处理
select
   sender_gps
from db_msg.tb_msg_source
limit 10;

-- 创建保存清洗后数据的表
create table db_msg.tb_msg_etl(
msg_time string comment "消息发送时间",
sender_name string comment "发送人昵称",
sender_account string comment "发送人账号",
sender_sex string comment "发送人性别",
sender_ip string comment "发送人ip地址",
sender_os string comment "发送人操作系统",
sender_phonetype string comment "发送人手机型号",
sender_network string comment "发送人网络类型",
sender_gps string comment "发送人的GPS定位",
receiver_name string comment "接收人昵称",
receiver_ip string comment "接收人IP",
receiver_account string comment "接收人账号",
receiver_os string comment "接收人操作系统",
receiver_phonetype string comment "接收人手机型号",
receiver_network string comment "接收人网络类型",
receiver_gps string comment "接收人的GPS定位",
receiver_sex string comment "接收人性别",
msg_type string comment "消息类型",
distance string comment "双方距离",
message string comment "消息内容",
msg_day string comment "消息日",
msg_hour string comment "消息小时",
sender_lng double comment "经度",
sender_lat double comment "纬度"
);

-- 保存清洗后的数据
INSERT OVERWRITE TABLE db_msg.tb_msg_etl
SELECT 
    *, 
    day(msg_time) as msg_day, 
    HOUR(msg_time) as msg_hour, 
    split(sender_gps, ',')[0] AS sender_lng,
    split(sender_gps, ',')[1] AS sender_lat
FROM tb_msg_source WHERE LENGTH(sender_gps) > 0;

-- 查看数据
select
    msg_time, msg_day, msg_hour, sender_gps, sender_lng, sender_lat
from db_msg.tb_msg_etl
limit 10;

-- 需求指标统计
-- 指标1：统计今日消息总量
-- 保存结果表
CREATE TABLE IF NOT EXISTS tb_rs_total_msg_cnt 
COMMENT "每日消息总量" AS 
SELECT 
    msg_day, 
    COUNT(*) AS total_msg_cnt 
FROM db_msg.tb_msg_etl
GROUP BY msg_day;

-- 指标2：统计每小时消息量、发送和接收用户数
select 
    from_unixtime(unix_timestamp(msg_time,'yyyy-MM-dd HH:mm:ss'),'HH') as hour,
    count(*) as total_msg,
    count(distinct sender_account) as total_sender,
    count(distinct receiver_account) as total_receiver
from tb_msg_source
group by from_unixtime(unix_timestamp(msg_time,'yyyy-MM-dd HH:mm:ss'),'HH');
-- 保存结果表
CREATE TABLE IF NOT EXISTS tb_rs_hour_msg_cnt 
COMMENT "每小时消息量趋势" AS  
SELECT  
    msg_hour, 
    COUNT(*) AS total_msg_cnt, 
    COUNT(DISTINCT sender_account) AS sender_usr_cnt, 
    COUNT(DISTINCT receiver_account) AS receiver_usr_cnt
FROM db_msg.tb_msg_etl GROUP BY msg_hour;

-- 指标3：统计今日各地区发送消息总量
CREATE TABLE IF NOT EXISTS tb_rs_loc_cnt
COMMENT '今日各地区发送消息总量' AS 
SELECT 
    msg_day,  
    sender_lng, 
    sender_lat, 
    COUNT(*) AS total_msg_cnt 
FROM db_msg.tb_msg_etl
GROUP BY msg_day, sender_lng, sender_lat;

-- 指标4：统计今日发送和接收用户人数
CREATE TABLE IF NOT EXISTS tb_rs_usr_cnt
COMMENT "今日发送消息人数、接受消息人数" AS
SELECT 
msg_day, 
COUNT(DISTINCT sender_account) AS sender_usr_cnt, 
COUNT(DISTINCT receiver_account) AS receiver_usr_cnt
FROM db_msg.tb_msg_etl
GROUP BY msg_day;

-- 指标5：统计发送消息条数最多的Top10用户
CREATE TABLE IF NOT EXISTS db_msg.tb_rs_s_user_top10
COMMENT "发送消息条数最多的Top10用户" AS
SELECT 
    sender_name AS username, 
    COUNT(*) AS sender_msg_cnt 
FROM db_msg.tb_msg_etl 
GROUP BY sender_name 
ORDER BY sender_msg_cnt DESC 
LIMIT 10;

-- 指标6：统计接收消息条数最多的Top10用户
CREATE TABLE IF NOT EXISTS db_msg.tb_rs_r_user_top10
COMMENT "接收消息条数最多的Top10用户" AS
SELECT 
receiver_name AS username, 
COUNT(*) AS receiver_msg_cnt 
FROM db_msg.tb_msg_etl 
GROUP BY receiver_name 
ORDER BY receiver_msg_cnt DESC 
LIMIT 10;

-- 指标7：统计发送人的手机型号分布情况
CREATE TABLE IF NOT EXISTS db_msg.tb_rs_sender_phone
COMMENT "发送人的手机型号分布" AS
SELECT 
    sender_phonetype, 
    COUNT(sender_account) AS cnt 
FROM db_msg.tb_msg_etl 
GROUP BY sender_phonetype;

-- 指标8：统计发送人的手机操作系统分布
CREATE TABLE IF NOT EXISTS db_msg.tb_rs_sender_os
COMMENT "发送人的OS分布" AS
SELECT
    sender_os, 
    COUNT(sender_account) AS cnt 
FROM db_msg.tb_msg_etl 
GROUP BY sender_os;