Create view from multiple queries - mysql

Question

I'm currently doing a sql script using the following tables in a database:
Menu table (contains the information about dishes):
+----------+--------------+--------+-------------+
| id_plato | nombre_plato | precio | tipo |
+----------+--------------+--------+-------------+
| 1 | peces | 100 | entrada |
| 2 | caca | 20 | rolls_fondo |
| 3 | plato1 | 200 | bajativo |
| 4 | plato2 | 200 | entrada |
| 5 | plato3 | 200 | entrada |
| 6 | plato4 | 200 | entrada |
| 7 | plato5 | 200 | entrada |
| 8 | plato6 | 200 | entrada |
| 9 | plato7 | 200 | entrada |
| 10 | plato8 | 200 | entrada |
| 11 | plato9 | 200 | entrada |
| 12 | plato10 | 200 | entrada |
| 13 | plato11 | 200 | entrada |
| 14 | plato1 | 200 | entrada |
+----------+--------------+--------+-------------+
Boleta table (contains the informatio of all sales):
+-----------+------+--------------+
| id_boleta | sexo | precio_final |
+-----------+------+--------------+
| 1 | m | 1 |
| 2 | f | 1 |
| 3 | f | 1 |
| 4 | m | 1 |
+-----------+------+--------------+
BoletaDetalle table (contains the information of each dish bought on a given sale):
+------------+-----------+----------+----------------+
| id_detalle | id_boleta | id_plato | precio_detalle |
+------------+-----------+----------+----------------+
| 1 | 1 | 1 | 1 |
| 2 | 1 | 1 | 1 |
| 3 | 1 | 2 | 1990 |
| 4 | 2 | 1 | 5 |
| 5 | 3 | 4 | 1 |
| 6 | 4 | 2 | 1 |
| 7 | 5 | 4 | 1 |
| 8 | 4 | 2 | 1 |
+------------+-----------+----------+----------------+
Basically, this is a small program for a small restaurant and I have been asked to show a quick report trough an sql script that displays a view containing the favorite dish of a certain group of costumers. For example, based on costumer's gender as follows:
| Sex | Type |
+------------------+
| M | entrada |
| F | bajativo |
I'm having a lot of trouble trying to figure this out despite of it being an easy task.
This is what I have so far:
DROP VIEW IF EXISTS v1;
CREATE VIEW v1 (Tipo, CantidadMujer, CantidadHombre)
AS
SELECT m.tipo as Tipo, COUNT(bd.id_plato) as 'Cantidad Mujer', COUNT(bd2.id_plato) as 'Cantidad Hombre'
FROM Menu m
LEFT JOIN BoletaDetalle bd
INNER JOIN Boleta b
on (bd.id_boleta = b.id_boleta AND b.sexo = 'f')
on bd.id_plato = m.id_plato AND m.tipo = 'entrada'
LEFT JOIN BoletaDetalle bd2
INNER JOIN Boleta b2
on (bd2.id_boleta = b2.id_boleta AND b2.sexo = 'm')
on bd2.id_plato = m.id_plato AND m.tipo = 'entrada'
GROUP BY(m.tipo);
SELECT * FROM v1;
I was thinking of creating a view like the one above with the amount of dishes bought per each gender (on each dish type) and then create a second view (the final one) by getting the maximum value per category. I'm really lost here so any help would be appreciated.

Answer 1

Are you looking for something like this?
CREATE VIEW sexo_tipo_view AS
SELECT b.sexo, m.tipo, COUNT(d.id_plato) total
FROM boletadetalle d JOIN boleta b
ON d.id_boleta = b.id_boleta JOIN menu m
ON d.id_plato = m.id_plato
GROUP BY b.sexo, m.tipo
ORDER BY sexo, total DESC;
CREATE VIEW sexo_tipo_favorites_view AS
SELECT sexo, tipo
FROM sexo_tipo_view
GROUP BY sexo;
SELECT s.sexo, COALESCE(v.tipo, '-') tipo
FROM
(
SELECT 'f' sexo UNION ALL
SELECT 'm'
) s LEFT JOIN sexo_tipo_favorites_view v
ON s.sexo = v.sexo;
or without views
SELECT s.sexo, COALESCE(v.tipo, '-') tipo
FROM
(
SELECT 'f' sexo UNION ALL
SELECT 'm'
) s LEFT JOIN
(
SELECT sexo, tipo
FROM
(
SELECT b.sexo, m.tipo, COUNT(d.id_plato) total
FROM boletadetalle d JOIN boleta b
ON d.id_boleta = b.id_boleta JOIN menu m
ON d.id_plato = m.id_plato
GROUP BY b.sexo, m.tipo
ORDER BY sexo, total DESC
) a
GROUP BY sexo
) v
ON s.sexo = v.sexo;
Sample output (in both cases):
| SEXO | TIPO |
|------|-------------|
| f | entrada |
| m | rolls_fondo |
Here is SQLFiddle demo