Update Trigger Distinct Date - mysql

Question

I'm doing a project and I got stuck on this trigger. This is the two tables involved.
---------------+---------------+------+-----+---------+----------------+
| 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 | |
+--------------+----------+------+-----+---------+----------------+
On this case, id_tra and id_tra_rec are related, and I need a trigger to update the dias_tra on dias_tra + 1 for id_tra = id_tra_rec when there is an INSERT on the second table image.
Thats relatively easy but the strange thing is that the Insert could have different data but the same date (fecha_rec), so the trigger must know if there is a row with the same id and the same date(fecha_rec) to not to update the dias_tra. Something like a select distinct. Here is what i tried:
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;
Sorry for my English, first time here, hope you understanding. If you need more information I'm around here :)

Answer 1

You don't say when datos_trabajadores is created so here's a trigger which checks and creates if necessary. I have used a simple count to check if check if id_tra_rec and fecha_rec already exist - this is an after insert trigger so a count of 1 means its the first one. note the debug_table is there to debug you should remove when you are happy.
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)

Answer 2

You can use exists to check if there is a record with the same data.
BEGIN
IF(EXISTS(select fecha_rec from datos_recogida where id_tra_rec=new.id_trarec and fecha_rec=new.fecha_rec)) THEN
//If the record exists do what you need.
ELSE
update datos_trabajadores set dias_tra = dias_tra +1 where id_tra=new.id_tra_rec
END IF;
END;

Answer 3

The solution of P.Salmon helped me to get a simplified way to do it. Thanks every body and hope helps somebody.
drop trigger if exists dias_tra;
delimiter $$
CREATE TRIGGER dias_tra AFTER INSERT ON datos_recogida FOR EACH ROW
BEGIN
DECLARE dias INT;
SET dias = (SELECT COUNT(DISTINCT fecha_rec) AS diasmes FROM datos_recogida WHERE id_tra_rec=NEW.id_tra_rec);
UPDATE datos_trabajadores SET dias_tra = dias where id_tra=NEW.id_tra_rec;
END; $$