老婆公司有个这样的需求：
查询出某游戏的用户回流信息，当用户连续两天登陆，则判定为2日回流，如果间隔一天登陆，则判定为3日回流，如果间隔5天登陆，则判定为7日回流。用户数据间隔时间短为14天（固定）。
准备数据
database语法和mysql一致。
创建表：
create table user_login(u_id int,login_date timestamp default current_timestamp);
插入数据：
DELIMITER //create procedure loop_insert()begindeclare days int;declare usrs int;declare mx int;declare i int;set days = 14;set usrs = 30;set mx = 500;set i = 1;repeat insert into user_login(u_id,login_date) values (floor((RAND() * usrs)),subdate(sysdate(),(RAND() * (days+1)))); set i = i + 1;until i >= mxend repeat;end//
call loop_insert();
最开始我想到的是用group_concat,sql是这样：
SELECT u_id, group_concat(distinct DATE_FORMAT(login_date, '%Y%m%d') order by DATE_FORMAT(login_date, '%Y%m%d') desc separator '-') AS yyyymmddFROM user_loginGROUP BY u_id;
后来想想日期转换成INTEGER相减是不准确的（比如跨月），而且这样显示并不能解决需求。
好吧，考虑行转列。
行转列
行转列，需要case when枚举，好在日期只有14天，可以做到：
SELECT u_id, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180413' THEN login_date ELSE '' END AS d20180413, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180414' THEN login_date ELSE '' END AS d20180414, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180415' THEN login_date ELSE '' END AS d20180415, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180416' THEN login_date ELSE '' END AS d20180416, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180417' THEN login_date ELSE '' END AS d20180417, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180418' THEN login_date ELSE '' END AS d20180418, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180419' THEN login_date ELSE '' END AS d20180419, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180420' THEN login_date ELSE '' END AS d20180420, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180421' THEN login_date ELSE '' END AS d20180421, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180422' THEN login_date ELSE '' END AS d20180422, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180423' THEN login_date ELSE '' END AS d20180423, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180424' THEN login_date ELSE '' END AS d20180424, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180425' THEN login_date ELSE '' END AS d20180425, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180426' THEN login_date ELSE '' END AS d20180426 FROM user_login
查询结果：
按用户合并
按用户合并日期，去重，用max可以保证单条数据，有数据置为1无数据置为0：
SELECT u_id, CASE WHEN MAX(d20180413) = '' THEN '0' ELSE '1' END AS isZ20180413, CASE WHEN MAX(d20180414) = '' THEN '0' ELSE '1' END AS isZ20180414, CASE WHEN MAX(d20180415) = '' THEN '0' ELSE '1' END AS isZ20180415, CASE WHEN MAX(d20180416) = '' THEN '0' ELSE '1' END AS isZ20180416, CASE WHEN MAX(d20180417) = '' THEN '0' ELSE '1' END AS isZ20180417, CASE WHEN MAX(d20180418) = '' THEN '0' ELSE '1' END AS isZ20180418, CASE WHEN MAX(d20180419) = '' THEN '0' ELSE '1' END AS isZ20180419, CASE WHEN MAX(d20180420) = '' THEN '0' ELSE '1' END AS isZ20180420, CASE WHEN MAX(d20180421) = '' THEN '0' ELSE '1' END AS isZ20180421, CASE WHEN MAX(d20180422) = '' THEN '0' ELSE '1' END AS isZ20180422, CASE WHEN MAX(d20180423) = '' THEN '0' ELSE '1' END AS isZ20180423, CASE WHEN MAX(d20180424) = '' THEN '0' ELSE '1' END AS isZ20180424, CASE WHEN MAX(d20180425) = '' THEN '0' ELSE '1' END AS isZ20180425, CASE WHEN MAX(d20180426) = '' THEN '0' ELSE '1' END AS isZ20180426 FROM (SELECT u_id, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180413' THEN login_date ELSE '' END AS d20180413, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180414' THEN login_date ELSE '' END AS d20180414, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180415' THEN login_date ELSE '' END AS d20180415, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180416' THEN login_date ELSE '' END AS d20180416, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180417' THEN login_date ELSE '' END AS d20180417, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180418' THEN login_date ELSE '' END AS d20180418, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180419' THEN login_date ELSE '' END AS d20180419, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180420' THEN login_date ELSE '' END AS d20180420, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180421' THEN login_date ELSE '' END AS d20180421, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180422' THEN login_date ELSE '' END AS d20180422, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180423' THEN login_date ELSE '' END AS d20180423, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180424' THEN login_date ELSE '' END AS d20180424, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180425' THEN login_date ELSE '' END AS d20180425, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180426' THEN login_date ELSE '' END AS d20180426 FROM user_login) t0 GROUP BY u_id
查询结果：
列转行
使用group_concat:
SELECT u_id, CONCAT(isZ20180413, isZ20180414, isZ20180415, isZ20180416, isZ20180417, isZ20180418, isZ20180419, isZ20180420, isZ20180421, isZ20180422, isZ20180423, isZ20180424, isZ20180425, isZ20180426) AS sumIsZ FROM (SELECT u_id, CASE WHEN MAX(d20180413) = '' THEN '0' ELSE '1' END AS isZ20180413, CASE WHEN MAX(d20180414) = '' THEN '0' ELSE '1' END AS isZ20180414, CASE WHEN MAX(d20180415) = '' THEN '0' ELSE '1' END AS isZ20180415, CASE WHEN MAX(d20180416) = '' THEN '0' ELSE '1' END AS isZ20180416, CASE WHEN MAX(d20180417) = '' THEN '0' ELSE '1' END AS isZ20180417, CASE WHEN MAX(d20180418) = '' THEN '0' ELSE '1' END AS isZ20180418, CASE WHEN MAX(d20180419) = '' THEN '0' ELSE '1' END AS isZ20180419, CASE WHEN MAX(d20180420) = '' THEN '0' ELSE '1' END AS isZ20180420, CASE WHEN MAX(d20180421) = '' THEN '0' ELSE '1' END AS isZ20180421, CASE WHEN MAX(d20180422) = '' THEN '0' ELSE '1' END AS isZ20180422, CASE WHEN MAX(d20180423) = '' THEN '0' ELSE '1' END AS isZ20180423, CASE WHEN MAX(d20180424) = '' THEN '0' ELSE '1' END AS isZ20180424, CASE WHEN MAX(d20180425) = '' THEN '0' ELSE '1' END AS isZ20180425, CASE WHEN MAX(d20180426) = '' THEN '0' ELSE '1' END AS isZ20180426 FROM (SELECT u_id, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180413' THEN login_date ELSE '' END AS d20180413, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180414' THEN login_date ELSE '' END AS d20180414, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180415' THEN login_date ELSE '' END AS d20180415, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180416' THEN login_date ELSE '' END AS d20180416, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180417' THEN login_date ELSE '' END AS d20180417, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180418' THEN login_date ELSE '' END AS d20180418, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180419' THEN login_date ELSE '' END AS d20180419, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180420' THEN login_date ELSE '' END AS d20180420, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180421' THEN login_date ELSE '' END AS d20180421, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180422' THEN login_date ELSE '' END AS d20180422, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180423' THEN login_date ELSE '' END AS d20180423, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180424' THEN login_date ELSE '' END AS d20180424, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180425' THEN login_date ELSE '' END AS d20180425, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180426' THEN login_date ELSE '' END AS d20180426 FROM user_login) t0 GROUP BY u_id) t1
查询结果：
统计
SELECT u_id, sumIsZ, CASE WHEN LOCATE('11', sumIsZ) > 0 THEN 2 ELSE 0 END AS is2Back,/*2日回流*/ CASE WHEN LOCATE('101', sumIsZ) > 0 THEN 3 ELSE 0 END AS is3Back,/*3日回流*/ CASE WHEN LOCATE('1001', sumIsZ) > 0 THEN 4 ELSE 0 END AS is4Back,/*4日回流*/ CASE WHEN LOCATE('10001', sumIsZ) > 0 THEN 5 ELSE 0 END AS is5Back,/*5日回流*/ CASE WHEN LOCATE('100001', sumIsZ) > 0 THEN 6 ELSE 0 END AS is6Back,/*6日回流*/ CASE WHEN LOCATE('1000001', sumIsZ) > 0 THEN 7 ELSE 0 END AS is7Back/*7日回流*/FROM (SELECT u_id, CONCAT(isZ20180413, isZ20180414, isZ20180415, isZ20180416, isZ20180417, isZ20180418, isZ20180419, isZ20180420, isZ20180421, isZ20180422, isZ20180423, isZ20180424, isZ20180425, isZ20180426) AS sumIsZ FROM (SELECT u_id, CASE WHEN MAX(d20180413) = '' THEN '0' ELSE '1' END AS isZ20180413, CASE WHEN MAX(d20180414) = '' THEN '0' ELSE '1' END AS isZ20180414, CASE WHEN MAX(d20180415) = '' THEN '0' ELSE '1' END AS isZ20180415, CASE WHEN MAX(d20180416) = '' THEN '0' ELSE '1' END AS isZ20180416, CASE WHEN MAX(d20180417) = '' THEN '0' ELSE '1' END AS isZ20180417, CASE WHEN MAX(d20180418) = '' THEN '0' ELSE '1' END AS isZ20180418, CASE WHEN MAX(d20180419) = '' THEN '0' ELSE '1' END AS isZ20180419, CASE WHEN MAX(d20180420) = '' THEN '0' ELSE '1' END AS isZ20180420, CASE WHEN MAX(d20180421) = '' THEN '0' ELSE '1' END AS isZ20180421, CASE WHEN MAX(d20180422) = '' THEN '0' ELSE '1' END AS isZ20180422, CASE WHEN MAX(d20180423) = '' THEN '0' ELSE '1' END AS isZ20180423, CASE WHEN MAX(d20180424) = '' THEN '0' ELSE '1' END AS isZ20180424, CASE WHEN MAX(d20180425) = '' THEN '0' ELSE '1' END AS isZ20180425, CASE WHEN MAX(d20180426) = '' THEN '0' ELSE '1' END AS isZ20180426 FROM (SELECT u_id, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180413' THEN login_date ELSE '' END AS d20180413, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180414' THEN login_date ELSE '' END AS d20180414, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180415' THEN login_date ELSE '' END AS d20180415, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180416' THEN login_date ELSE '' END AS d20180416, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180417' THEN login_date ELSE '' END AS d20180417, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180418' THEN login_date ELSE '' END AS d20180418, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180419' THEN login_date ELSE '' END AS d20180419, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180420' THEN login_date ELSE '' END AS d20180420, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180421' THEN login_date ELSE '' END AS d20180421, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180422' THEN login_date ELSE '' END AS d20180422, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180423' THEN login_date ELSE '' END AS d20180423, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180424' THEN login_date ELSE '' END AS d20180424, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180425' THEN login_date ELSE '' END AS d20180425, CASE DATE_FORMAT(login_date, '%Y%m%d') WHEN '20180426' THEN login_date ELSE '' END AS d20180426 FROM user_login) t0 GROUP BY u_id) t1) t2; 查询结果：
结语
老婆，明天照着这个逻辑写就可以了，么么哒。（2018年4月26日23点50分）