我正在做一个项目,却被这个触发器卡住了.这是涉及的两个表.

    ---------------+---------------+------+-----+---------+----------------+
| Field         | Type          | Null | Key | Default | Extra          |
+---------------+---------------+------+-----+---------+----------------+
| id_tra        | int(11)       | NO   | PRI | NULL    | auto_increment |
| nombre_tra    | varchar(100)  | NO   |     | NULL    |                |
| apellidos_tra | varchar(100)  | NO   |     | NULL    |                |
| dni_tra       | varchar(1000) | NO   |     | NULL    |                |
| telefono_tra  | int(10)       | NO   |     | NULL    |                |
| falta_tra     | date          | NO   |     | NULL    |                |
| dias_tra      | int(255)      | NO   |     | NULL    |                |
+---------------+---------------+------+-----+---------+----------------+

+--------------+----------+------+-----+---------+----------------+
| Field        | Type     | Null | Key | Default | Extra          |
+--------------+----------+------+-----+---------+----------------+
| id_rec       | int(11)  | NO   | PRI | NULL    | auto_increment |
| id_tra_rec   | int(11)  | NO   | MUL | NULL    |                |
| id_var_rec   | int(11)  | NO   | MUL | NULL    |                |
| fecha_rec    | date     | NO   |     | NULL    |                |
| cantidad_rec | int(255) | NO   |     | NULL    |                |
+--------------+----------+------+-----+---------+----------------+

在这种情况下,id_tra和id_tra_rec是相关的,并且当第二张表映像上有INSERT时,我需要一个触发器来更新dias_tra 1上的dias_tra来更新id_tra = id_tra_rec.
那是相对容易的,但奇怪的是,Insert可以具有不同的数据,但是具有相同的日期(fecha_rec),因此触发器必须知道是否存在具有相同ID和相同日期(fecha_rec)的行,以不更新dias_tra .像精选不同的东西.这是我尝试过的：

create trigger dias_tra 
after insert on datos_recogida
for each row
begin
if (select fecha_rec from datos_recogida where id_tra_rec=new.id_trarec and fecha_rec=new.fecha_rec)
update datos_trabajadores set dias_tra = dias_tra +1 where id_tra=new.id_tra_rec
end if;
end;

对不起,我的英文,第一次来,希望您能谅解.如果您需要更多信息,我在这里:)

解决方法:

您无需说datos_trabajadores的创建时间,因此这里有一个触发器,可以根据需要进行检查和创建.我使用了一个简单的计数来检查是否已存在id_tra_rec和fecha_rec-这是插入后触发,因此计数1表示其第一个.请注意,您可以在需要调试时删除debug_table进行调试.

drop table if exists datos_recogida,datos_trabajadores;
create table datos_trabajadores
( id_tra         int(11)  auto_increment primary key,
 nombre_tra     varchar(100)  ,
 apellidos_tra  varchar(100)  ,
 dni_tra        varchar(1000) ,
 telefono_tra   int(10)       ,
 falta_tra      date          ,
 dias_tra       int(255)      )
;
create table datos_recogida
( id_rec        int(11)   auto_increment primary key,
 id_tra_rec    int(11)  ,
 id_var_rec    int(11)  ,
 fecha_rec     date     ,
 cantidad_rec  int(255) );

drop trigger if exists t;
delimiter $$

create trigger t after insert on datos_recogida
for each row
begin
    if (select count(*) from datos_recogida where id_tra_rec = new.id_tra_rec and fecha_rec = new.fecha_rec) = 1 then
        insert into debug_table(msg) values (concat('not found:',new.id_tra_rec,':',new.fecha_rec));
        if not exists(select 1 from datos_trabajadores where dias_tra = new.id_tra_rec) then
            insert into debug_table(msg) values ('inserting');
            insert into datos_trabajadores(dias_tra,nombre_tra) values (new.id_tra_rec,1);
        else
            insert into debug_table(msg) values ('Updating');
            update datos_trabajadores
                set nombre_tra = nombre_tra + 1
                where dias_tra = new.id_tra_rec;
        end if;
    end if;

end $$
delimiter ;

truncate table debug_table;
truncate table datos_recogida;
truncate table datos_trabajadores;

insert into datos_recogida (id_tra_rec,fecha_rec) 
values
(1,'2019-01-01'),
(1,'2019-01-01'),
(1,'2019-01-02');

select * from debug_table;
select * from datos_trabajadores;

MariaDB [sandbox]> select * from debug_table;
+----+------------------------+------+
| id | msg                    | MSG2 |
+----+------------------------+------+
|  1 | not found:1:2019-01-01 | NULL |
|  2 | inserting              | NULL |
|  3 | not found:1:2019-01-02 | NULL |
|  4 | Updating               | NULL |
+----+------------------------+------+
4 rows in set (0.00 sec)

MariaDB [sandbox]> select * from datos_trabajadores;
+--------+------------+---------------+---------+--------------+-----------+----------+
| id_tra | nombre_tra | apellidos_tra | dni_tra | telefono_tra | falta_tra | dias_tra |
+--------+------------+---------------+---------+--------------+-----------+----------+
|      1 | 2          | NULL          | NULL    |         NULL | NULL      |        1 |
+--------+------------+---------------+---------+--------------+-----------+----------+
1 row in set (0.00 sec)