Question

我有这些表的数据库：

drop table if exists events1;
create table if not exists events1(
    time_stamp          decimal(16,6),     
    message             char(90)        not null default 'defult message'
);

drop table if exists events2;
create table if not exists events2(
    time_stamp          decimal(16,6),     
    message             char(90)        not null default 'defult message'
);

drop table if exists events3;
create table if not exists events3(
    time_stamp          decimal(16,6),     
    message             char(90)        not null default 'defult message'
);

insert into events1 (time_stamp,message) values (1485193300,"a1");
insert into events1 (time_stamp,message) values (1485193600,"b1");
insert into events1 (time_stamp,message) values (1485193900,"c1");

insert into events2 (time_stamp,message) values (1485193300,"a1");
insert into events2 (time_stamp,message) values (1485193600,"b2");
insert into events2 (time_stamp,message) values (1485193900,"c3");

insert into events3 (time_stamp,message) values (1485193300,"a1");
insert into events3 (time_stamp,message) values (1485193600,"b2");
insert into events3 (time_stamp,message) values (1485193900,"c3");

我正在尝试使用3个参数构建存储过程：

start_time (int) (in epoch) 
end_time   (int) (in epoch) 
interval   (int) (in epoch)

我不是这个程序，将迭代 start_time ，步骤 interval 直到end_time，并在每次迭代时，获得三个表的并集，根据步骤和间隔。

类似的东西：

DELIMITER //
CREATE PROCEDURE get_events
(IN start_time INT,
 IN end_time INT,
 IN interval INT,
)
BEGIN
      while [ start_time <= end_time]
          do
             next_time = start_time + interval
             select * 
             from  events1
             where start_time <= time_stamp and time_stamp <= next_time

             union 

             select * 
             from  events2
             where start_time <= time_stamp and time_stamp <= next_time

             union 

             select * 
             from  events3
             where start_time <= time_stamp and time_stamp <= next_time

             start_time = start_time + interval


      end while

END //
DELIMITER ;

我知道我有语法错误，我不知道如何返回结果并在WHERE情况下以给定的间隔迭代3个表的并集。

请告知。

Answer 1

语法错误是什么？

[是无效的语法;可能是(中的WHILE？

a = a + b是无效的语法;请参阅SET命令。

拥有3个具有相同架构的表是通常一个糟糕的设计。

使用CHAR代替VARCHAR我们通常一个坏主意。

Answer 2

INSERT INTO "table name"
select * 
   from  events1
   where start_time <= time_stamp and time_stamp <= next_time

   union 

   select * 
   from  events2
   where start_time <= time_stamp and time_stamp <= next_time

   union 

   select * 
   from  events3
   where start_time <= time_stamp and time_stamp <= next_time

这会将查询存储在表中，然后您可以遍历该表。不知道那是不是你要的。

以下是文档： https://dev.mysql.com/doc/refman/5.7/en/insert-select.html

尝试编写具有开始时间和结束时间的存储过程

2 个答案: