22.储存过程

储存过程其实是多个sql的集合，常常用于一些数据整合或者定时任务的执行。以下是我第一个储存过程留念。

BEGIN
    
    declare now_time datetime;#当前系统时间
    declare start_time datetime;#开始时间
    declare end_time datetime;#结束时间

#搬运是时间为空，则取7天前的数据
if aim_time is not null then
    set now_time = aim_time;
    set start_time = DATE_SUB(timestamp(date(now())), INTERVAL 7 DAY);
    set end_time = DATE_SUB(timestamp(date(now())), INTERVAL 6 DAY);
else
    set now_time = now();
    set start_time = timestamp(adddate(date(now_time), -1));
    set end_time = timestamp(date(now_time));
end if;

#临时表不能重复
DROP TEMPORARY TABLE IF EXISTS `t_temp_user_device_info`;
#最终成型的表结构，此为临时表
CREATE TEMPORARY TABLE `t_temp_user_device_info` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
    `device_info_id` varchar(20) COLLATE utf8_general_ci NOT NULL COMMENT '设备主键',
    `did` varchar(20) COLLATE utf8_general_ci NOT NULL COMMENT '设备号',
  `create_time` datetime DEFAULT NULL COMMENT '激活时间',
  PRIMARY KEY (`id`)
);

#将必要信息存入临时表
INSERT INTO t_temp_user_device_info (device_info_id, did, create_time)
SELECT t2.id, t1.did, t1.create_time
FROM (
    SELECT did, create_time FROM u_user_device_info where type = 1 AND create_time BETWEEN start_time AND end_time
) t1
INNER JOIN t_device_info t2 on t2.did = t1.did;

#把数据插入正式表
INSERT INTO t_count_user_device_info (did, reg_code, phone, path, sex, height, birthday, insterests, address, school)
SELECT t4.did, t1.reg_code, t2.phone, t3.path, t3.sex, t3.height, t3.birthday, t3.interests, t3.address, t3.school
FROM t_temp_user_device_info t4 
LEFT JOIN t_device_reg_code_info t1 ON t4.did = t1.did
LEFT JOIN t_device_phone t2 ON t4.did = t2.did
LEFT JOIN t_bady_info t3 ON t4.device_info_id = t3.device_info_id;

#SELECT * FROM t_count_user_device_info;

#判断并删除临时表
TRUNCATE TABLE t_temp_user_device_info;
DROP TEMPORARY TABLE IF EXISTS t_temp_user_device_info;

END

 sql中sum()函数和if的搭配用法。

SELECT COUNT(*) total, sum(if(phone is null, 1, 0)) pnum, sum(if(birthday is null, 1, 0)) bnum
FROM (
SELECT t4.did, t1.reg_code, t2.phone, t3.path, t3.sex, t3.height, t3.birthday, t3.interests, t3.address, t3.school, t4.create_time
FROM t_temp_user_device_info t4 
LEFT JOIN t_device_reg_code_info t1 ON t4.did = t1.did
LEFT JOIN t_device_phone t2 ON t4.did = t2.did
LEFT JOIN t_bady_info t3 ON t4.device_info_id = t3.device_info_id
) tt;