MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| Tienda_peliculas   |
| adrian_lopez       |
| aplicacion_cadena  |
| app_login          |
| biblioteca         |
| cadena             |
| cumple             |
| fechas_cadenas     |
| hospital_db        |
| information_schema |
| inventario_prueba  |
| mysql              |
| parcial1           |
| performance_schema |
| phpmyadmin         |
| simulacro          |
| subconsultas       |
| test               |
| veterinaria        |
+--------------------+
19 rows in set (0,002 sec)

MariaDB [(none)]> create database Fechas;
Query OK, 1 row affected (0,001 sec)

MariaDB [(none)]> CREATE TABLE estudiante (
    ->     carnet INT PRIMARY KEY,
    ->     nombre VARCHAR(100) NOT NULL,
    ->     fechamatricula DATE,
    ->     fechanacimiento DATE,
    ->     sexo CHAR(1) -- 'm' o 'f'
    -> );
ERROR 1046 (3D000): No database selected
MariaDB [(none)]> use Fechas;
Database changed
MariaDB [Fechas]> CREATE TABLE estudiante (
    ->     carnet INT PRIMARY KEY,
    ->     nombre VARCHAR(100) NOT NULL,
    ->     fechamatricula DATE,
    ->     fechanacimiento DATE,
    ->     sexo CHAR(1) -- 'm' o 'f'
    -> );
Query OK, 0 rows affected (0,014 sec)

MariaDB [Fechas]> show tables;
+------------------+
| Tables_in_Fechas |
+------------------+
| estudiante       |
+------------------+
1 row in set (0,001 sec)

MariaDB [Fechas]> describe estudiante;
+-----------------+--------------+------+-----+---------+-------+
| Field           | Type         | Null | Key | Default | Extra |
+-----------------+--------------+------+-----+---------+-------+
| carnet          | int(11)      | NO   | PRI | NULL    |       |
| nombre          | varchar(100) | NO   |     | NULL    |       |
| fechamatricula  | date         | YES  |     | NULL    |       |
| fechanacimiento | date         | YES  |     | NULL    |       |
| sexo            | char(1)      | YES  |     | NULL    |       |
+-----------------+--------------+------+-----+---------+-------+
5 rows in set (0,008 sec)

MariaDB [Fechas]> CREATE TABLE materia (
    ->     codigom INT PRIMARY KEY,
    ->     descripcion VARCHAR(100) NOT NULL,
    ->     valor DECIMAL(10,2) NOT NULL
    -> );
Query OK, 0 rows affected (0,009 sec)

MariaDB [Fechas]> show tables;
+------------------+
| Tables_in_Fechas |
+------------------+
| estudiante       |
| materia          |
+------------------+
2 rows in set (0,001 sec)

MariaDB [Fechas]> describe materia;
+-------------+---------------+------+-----+---------+-------+
| Field       | Type          | Null | Key | Default | Extra |
+-------------+---------------+------+-----+---------+-------+
| codigom     | int(11)       | NO   | PRI | NULL    |       |
| descripcion | varchar(100)  | NO   |     | NULL    |       |
| valor       | decimal(10,2) | NO   |     | NULL    |       |
+-------------+---------------+------+-----+---------+-------+
3 rows in set (0,003 sec)

MariaDB [Fechas]> CREATE TABLE estmat (
    ->     carnet INT,
    ->     codigom INT,
    ->     PRIMARY KEY (carnet, codigom),
    ->     FOREIGN KEY (carnet) REFERENCES estudiante(carnet),
    ->     FOREIGN KEY (codigom) REFERENCES materia(codigom)
    -> );
Query OK, 0 rows affected (0,016 sec)

MariaDB [Fechas]> INSERT INTO estudiante (carnet, nombre, fechamatricula, fechanacimiento, sexo) VALUES
    -> (1, 'maria', '2010-01-15', '1966-05-13', 'f'),
    -> (2, 'juana', '2010-06-08', '1973-01-22', 'f'),
    -> (3, 'carlos', '2010-06-28', '1976-03-05', 'm'),
    -> (4, 'Maria Parra', '2010-06-11', '1976-08-15', 'f'),
    -> (5, 'Pablo Neruda', '2011-02-13', '1990-08-25', 'm'),
    -> (6, 'Bladimir Palacio', '2011-02-04', '1994-09-03', 'm'),
    -> (7, 'Apolonia Serrano', '2011-02-28', '1994-03-09', 'f'),
    -> (8, 'Federico Serrano', '2011-03-05', '1991-06-10', 'm');
Query OK, 8 rows affected (0,006 sec)
Records: 8  Duplicates: 0  Warnings: 0

MariaDB [Fechas]> INSERT INTO materia (codigom, descripcion, valor) VALUES
    -> (1, 'software I', 320000),
    -> (2, 'software II', 328000),
    -> (3, 'software III', 400000),
    -> (4, 'matematicas', 300000),
    -> (5, 'ingles', 300000);
Query OK, 5 rows affected (0,008 sec)
Records: 5  Duplicates: 0  Warnings: 0

MariaDB [Fechas]> INSERT INTO estmat (carnet, codigom) VALUES
    -> (1, 3),
    -> (1, 5),
    -> (2, 2),
    -> (2, 3),
    -> (2, 4),
    -> (3, 4),
    -> (3, 1),
    -> (4, 4),
    -> (4, 5),
    -> (5, 2),
    -> (5, 5),
    -> (6, 1),
    -> (6, 5),
    -> (7, 3),
    -> (7, 4),
    -> (8, 1),
    -> (8, 4),
    -> (8, 5);
Query OK, 18 rows affected (0,009 sec)
Records: 18  Duplicates: 0  Warnings: 0

MariaDB [Fechas]> show tables
    -> ;
+------------------+
| Tables_in_Fechas |
+------------------+
| estmat           |
| estudiante       |
| materia          |
+------------------+
3 rows in set (0,001 sec)

MariaDB [Fechas]> select * from estmat;
+--------+---------+
| carnet | codigom |
+--------+---------+
|      1 |       3 |
|      1 |       5 |
|      2 |       2 |
|      2 |       3 |
|      2 |       4 |
|      3 |       1 |
|      3 |       4 |
|      4 |       4 |
|      4 |       5 |
|      5 |       2 |
|      5 |       5 |
|      6 |       1 |
|      6 |       5 |
|      7 |       3 |
|      7 |       4 |
|      8 |       1 |
|      8 |       4 |
|      8 |       5 |
+--------+---------+
18 rows in set (0,001 sec)

MariaDB [Fechas]> select * from estudiante;
+--------+------------------+----------------+-----------------+------+
| carnet | nombre           | fechamatricula | fechanacimiento | sexo |
+--------+------------------+----------------+-----------------+------+
|      1 | maria            | 2010-01-15     | 1966-05-13      | f    |
|      2 | juana            | 2010-06-08     | 1973-01-22      | f    |
|      3 | carlos           | 2010-06-28     | 1976-03-05      | m    |
|      4 | Maria Parra      | 2010-06-11     | 1976-08-15      | f    |
|      5 | Pablo Neruda     | 2011-02-13     | 1990-08-25      | m    |
|      6 | Bladimir Palacio | 2011-02-04     | 1994-09-03      | m    |
|      7 | Apolonia Serrano | 2011-02-28     | 1994-03-09      | f    |
|      8 | Federico Serrano | 2011-03-05     | 1991-06-10      | m    |
+--------+------------------+----------------+-----------------+------+
8 rows in set (0,001 sec)

MariaDB [Fechas]> select * from materia;
+---------+--------------+-----------+
| codigom | descripcion  | valor     |
+---------+--------------+-----------+
|       1 | software I   | 320000.00 |
|       2 | software II  | 328000.00 |
|       3 | software III | 400000.00 |
|       4 | matematicas  | 300000.00 |
|       5 | ingles       | 300000.00 |
+---------+--------------+-----------+
5 rows in set (0,001 sec)

MariaDB [Fechas]> select COUNT(*) AS estudiantes_70s FROM estudiante WHERE SUBSTR(fechanacimiento, 1, 4) BETWEEN '1970' AND '1979';
+-----------------+
| estudiantes_70s |
+-----------------+
|               3 |
+-----------------+
1 row in set (0,008 sec)

MariaDB [Fechas]> SELECT nombre, fechanacimiento FROM estudiante WHERE SUBSTR(fechanacimiento, 1, 4) BETWEEN '2005' AND '2009';
Empty set (0,001 sec)

MariaDB [Fechas]> SELECT nombre, fechanacimiento
    -> FROM estudiante
    -> WHERE SUBSTR(fechanacimiento, 1, 4) BETWEEN '1991' AND '1995';
+------------------+-----------------+
| nombre           | fechanacimiento |
+------------------+-----------------+
| Bladimir Palacio | 1994-09-03      |
| Apolonia Serrano | 1994-03-09      |
| Federico Serrano | 1991-06-10      |
+------------------+-----------------+
3 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT nombre, fechanacimiento
    -> FROM estudiante
    -> WHERE fechanacimiento < '1986-01-01';
+-------------+-----------------+
| nombre      | fechanacimiento |
+-------------+-----------------+
| maria       | 1966-05-13      |
| juana       | 1973-01-22      |
| carlos      | 1976-03-05      |
| Maria Parra | 1976-08-15      |
+-------------+-----------------+
4 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT nombre, (2011 - CAST(SUBSTR(fechanacimiento, 1, 4) AS UNSIGNED)) AS edad FROM estudiante;
+------------------+------+
| nombre           | edad |
+------------------+------+
| maria            |   45 |
| juana            |   38 |
| carlos           |   35 |
| Maria Parra      |   35 |
| Pablo Neruda     |   21 |
| Bladimir Palacio |   17 |
| Apolonia Serrano |   17 |
| Federico Serrano |   20 |
+------------------+------+
8 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT descripcion, valor, CASE WHEN valor > 300000 THEN 'cara' ELSE 'economica' END AS mensaje FROM materia;
+--------------+-----------+-----------+
| descripcion  | valor     | mensaje   |
+--------------+-----------+-----------+
| software I   | 320000.00 | cara      |
| software II  | 328000.00 | cara      |
| software III | 400000.00 | cara      |
| matematicas  | 300000.00 | economica |
| ingles       | 300000.00 | economica |
+--------------+-----------+-----------+
5 rows in set (0,001 sec)

MariaDB [Fechas]> ALTER TABLE estudiante ADD COLUMN edad int;
Query OK, 0 rows affected (0,013 sec)
Records: 0  Duplicates: 0  Warnings: 0

MariaDB [Fechas]> describe estudiante;
+-----------------+--------------+------+-----+---------+-------+
| Field           | Type         | Null | Key | Default | Extra |
+-----------------+--------------+------+-----+---------+-------+
| carnet          | int(11)      | NO   | PRI | NULL    |       |
| nombre          | varchar(100) | NO   |     | NULL    |       |
| fechamatricula  | date         | YES  |     | NULL    |       |
| fechanacimiento | date         | YES  |     | NULL    |       |
| sexo            | char(1)      | YES  |     | NULL    |       |
| edad            | int(11)      | YES  |     | NULL    |       |
+-----------------+--------------+------+-----+---------+-------+
6 rows in set (0,002 sec)

MariaDB [Fechas]> UPDATE estudiante
    -> SET edad = 2011 - CAST(SUBSTR(fechanacimiento, 1, 4) AS UNSIGNED);
Query OK, 8 rows affected (0,004 sec)
Rows matched: 8  Changed: 8  Warnings: 0

MariaDB [Fechas]> select * from estudiante;
+--------+------------------+----------------+-----------------+------+------+
| carnet | nombre           | fechamatricula | fechanacimiento | sexo | edad |
+--------+------------------+----------------+-----------------+------+------+
|      1 | maria            | 2010-01-15     | 1966-05-13      | f    |   45 |
|      2 | juana            | 2010-06-08     | 1973-01-22      | f    |   38 |
|      3 | carlos           | 2010-06-28     | 1976-03-05      | m    |   35 |
|      4 | Maria Parra      | 2010-06-11     | 1976-08-15      | f    |   35 |
|      5 | Pablo Neruda     | 2011-02-13     | 1990-08-25      | m    |   21 |
|      6 | Bladimir Palacio | 2011-02-04     | 1994-09-03      | m    |   17 |
|      7 | Apolonia Serrano | 2011-02-28     | 1994-03-09      | f    |   17 |
|      8 | Federico Serrano | 2011-03-05     | 1991-06-10      | m    |   20 |
+--------+------------------+----------------+-----------------+------+------+
8 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT nombre, edad, CASE WHEN edad > 30 THEN 'hombre mayor' ELSE 'joven en desarrollo' END AS mensaje FROM estudiante;
+------------------+------+---------------------+
| nombre           | edad | mensaje             |
+------------------+------+---------------------+
| maria            |   45 | hombre mayor        |
| juana            |   38 | hombre mayor        |
| carlos           |   35 | hombre mayor        |
| Maria Parra      |   35 | hombre mayor        |
| Pablo Neruda     |   21 | joven en desarrollo |
| Bladimir Palacio |   17 | joven en desarrollo |
| Apolonia Serrano |   17 | joven en desarrollo |
| Federico Serrano |   20 | joven en desarrollo |
+------------------+------+---------------------+
8 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT descripcion, valor, CASE WHEN valor > 200000 AND valor <= 300000 THEN 'materia economica' ELSE 'cara' END AS mensaje FROM materia;
+--------------+-----------+-------------------+
| descripcion  | valor     | mensaje           |
+--------------+-----------+-------------------+
| software I   | 320000.00 | cara              |
| software II  | 328000.00 | cara              |
| software III | 400000.00 | cara              |
| matematicas  | 300000.00 | materia economica |
| ingles       | 300000.00 | materia economica |
+--------------+-----------+-------------------+
5 rows in set (0,002 sec)

MariaDB [Fechas]> CREATE TABLE Repazo2 (
    ->     codigo INT PRIMARY KEY,
    ->     nombre VARCHAR(100) NOT NULL,
    ->     sexo VARCHAR(10) NOT NULL,
    ->     fechanacimiento DATE NOT NULL,
    ->     nrohijos INT
    -> );
Query OK, 0 rows affected (0,016 sec)

MariaDB [Fechas]> show tables;
+------------------+
| Tables_in_Fechas |
+------------------+
| Repazo2          |
| estmat           |
| estudiante       |
| materia          |
+------------------+
4 rows in set (0,001 sec)

MariaDB [Fechas]> INSERT INTO Repazo2 (codigo, nombre, sexo, fechanacimiento, nrohijos) VALUES
    -> (111222, 'carlos ramirez', 'hombre', '1969-04-04', 2),
    -> (333666, 'marina ruiz', 'mujer', '1978-12-15', 3),
    -> (999111, 'veronica gonzalez', 'mujer', '1982-03-30', 1),
    -> (888777, 'isabel betancur', 'mujer', '1977-11-15', 1),
    -> (333777, 'gladys bermudez', 'mujer', '1979-01-01', 2),
    -> (444666, 'sandra henao', 'mujer', '1982-11-25', 3),
    -> (555777, 'mario gomez', 'hombre', '1982-05-29', 2),
    -> (111333, 'andrea gutierrez', 'mujer', '1985-04-12', 1),
    -> (444777, 'carlos sepulveda', 'hombre', '1974-01-10', 1),
    -> (555333, 'fernando perez', 'hombre', '1980-11-11', 4),
    -> (666555, 'juliana arredondo', 'mujer', '1988-12-31', 2);
Query OK, 11 rows affected (0,007 sec)
Records: 11  Duplicates: 0  Warnings: 0

MariaDB [Fechas]> select * from Repazo2;
+--------+-------------------+--------+-----------------+----------+
| codigo | nombre            | sexo   | fechanacimiento | nrohijos |
+--------+-------------------+--------+-----------------+----------+
| 111222 | carlos ramirez    | hombre | 1969-04-04      |        2 |
| 111333 | andrea gutierrez  | mujer  | 1985-04-12      |        1 |
| 333666 | marina ruiz       | mujer  | 1978-12-15      |        3 |
| 333777 | gladys bermudez   | mujer  | 1979-01-01      |        2 |
| 444666 | sandra henao      | mujer  | 1982-11-25      |        3 |
| 444777 | carlos sepulveda  | hombre | 1974-01-10      |        1 |
| 555333 | fernando perez    | hombre | 1980-11-11      |        4 |
| 555777 | mario gomez       | hombre | 1982-05-29      |        2 |
| 666555 | juliana arredondo | mujer  | 1988-12-31      |        2 |
| 888777 | isabel betancur   | mujer  | 1977-11-15      |        1 |
| 999111 | veronica gonzalez | mujer  | 1982-03-30      |        1 |
+--------+-------------------+--------+-----------------+----------+
11 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT COUNT(*) AS total_mujeres_nombre_z FROM Repazo2 WHERE sexo = 'mujer' AND nombre LIKE '%z';
+------------------------+
| total_mujeres_nombre_z |
+------------------------+
|                      4 |
+------------------------+
1 row in set (0,001 sec)

MariaDB [Fechas]> describe Repazo2;
+-----------------+--------------+------+-----+---------+-------+
| Field           | Type         | Null | Key | Default | Extra |
+-----------------+--------------+------+-----+---------+-------+
| codigo          | int(11)      | NO   | PRI | NULL    |       |
| nombre          | varchar(100) | NO   |     | NULL    |       |
| sexo            | varchar(10)  | NO   |     | NULL    |       |
| fechanacimiento | date         | NO   |     | NULL    |       |
| nrohijos        | int(11)      | YES  |     | NULL    |       |
+-----------------+--------------+------+-----+---------+-------+
5 rows in set (0,001 sec)

MariaDB [Fechas]> select COUNT(*) AS estudiantes_70s FROM Repazo2 WHERE SUBSTR(fechanacimiento, 1, 4) BETWEEN '1970' AND '1979';
+-----------------+
| estudiantes_70s |
+-----------------+
|               4 |
+-----------------+
1 row in set (0,001 sec)

MariaDB [Fechas]> SELECT nombre, fechanacimiento,
    ->        YEAR(CURDATE()) - CAST(SUBSTR(fechanacimiento,1,4) AS UNSIGNED) AS edad
    -> FROM Repazo2
    -> WHERE (YEAR(CURDATE()) - CAST(SUBSTR(fechanacimiento,1,4) AS UNSIGNED)) BETWEEN 25 AND 30;
Empty set (0,001 sec)

MariaDB [Fechas]> select * from Repazo2;
+--------+-------------------+--------+-----------------+----------+
| codigo | nombre            | sexo   | fechanacimiento | nrohijos |
+--------+-------------------+--------+-----------------+----------+
| 111222 | carlos ramirez    | hombre | 1969-04-04      |        2 |
| 111333 | andrea gutierrez  | mujer  | 1985-04-12      |        1 |
| 333666 | marina ruiz       | mujer  | 1978-12-15      |        3 |
| 333777 | gladys bermudez   | mujer  | 1979-01-01      |        2 |
| 444666 | sandra henao      | mujer  | 1982-11-25      |        3 |
| 444777 | carlos sepulveda  | hombre | 1974-01-10      |        1 |
| 555333 | fernando perez    | hombre | 1980-11-11      |        4 |
| 555777 | mario gomez       | hombre | 1982-05-29      |        2 |
| 666555 | juliana arredondo | mujer  | 1988-12-31      |        2 |
| 888777 | isabel betancur   | mujer  | 1977-11-15      |        1 |
| 999111 | veronica gonzalez | mujer  | 1982-03-30      |        1 |
+--------+-------------------+--------+-----------------+----------+
11 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT nombre, fechanacimiento,
    ->        (2011 - CAST(SUBSTR(fechanacimiento,1,4) AS UNSIGNED)) AS edad
    -> FROM Repazo2
    -> WHERE (2011 - CAST(SUBSTR(fechanacimiento,1,4) AS UNSIGNED)) BETWEEN 25 AND 30;
+-------------------+-----------------+------+
| nombre            | fechanacimiento | edad |
+-------------------+-----------------+------+
| andrea gutierrez  | 1985-04-12      |   26 |
| sandra henao      | 1982-11-25      |   29 |
| mario gomez       | 1982-05-29      |   29 |
| veronica gonzalez | 1982-03-30      |   29 |
+-------------------+-----------------+------+
4 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT SUM(nrohijos) AS total_hijos FROM Repazo2;
+-------------+
| total_hijos |
+-------------+
|          22 |
+-------------+
1 row in set (0,001 sec)

MariaDB [Fechas]> SELECT nrohijos, COUNT(*) AS total_personas FROM Repazo2 GROUP BY nrohijos;
+----------+----------------+
| nrohijos | total_personas |
+----------+----------------+
|        1 |              4 |
|        2 |              4 |
|        3 |              2 |
|        4 |              1 |
+----------+----------------+
4 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT COUNT(*) AS total_carlos FROM Repazo2 WHERE nombre LIKE 'carlos%';
+--------------+
| total_carlos |
+--------------+
|            2 |
+--------------+
1 row in set (0,001 sec)

MariaDB [Fechas]> SELECT COUNT(*) AS total_mujeres_menores_22 FROM Repazo2 WHERE sexo = 'mujer' AND SUBSTR(fechanacimiento, 1, 4) >= '1989';
+--------------------------+
| total_mujeres_menores_22 |
+--------------------------+
|                        0 |
+--------------------------+
1 row in set (0,002 sec)

MariaDB [Fechas]> SELECT * FROM Rapaz2;
ERROR 1146 (42S02): Table 'Fechas.Rapaz2' doesn't exist
MariaDB [Fechas]> SELECT * FROM Repazo2;
+--------+-------------------+--------+-----------------+----------+
| codigo | nombre            | sexo   | fechanacimiento | nrohijos |
+--------+-------------------+--------+-----------------+----------+
| 111222 | carlos ramirez    | hombre | 1969-04-04      |        2 |
| 111333 | andrea gutierrez  | mujer  | 1985-04-12      |        1 |
| 333666 | marina ruiz       | mujer  | 1978-12-15      |        3 |
| 333777 | gladys bermudez   | mujer  | 1979-01-01      |        2 |
| 444666 | sandra henao      | mujer  | 1982-11-25      |        3 |
| 444777 | carlos sepulveda  | hombre | 1974-01-10      |        1 |
| 555333 | fernando perez    | hombre | 1980-11-11      |        4 |
| 555777 | mario gomez       | hombre | 1982-05-29      |        2 |
| 666555 | juliana arredondo | mujer  | 1988-12-31      |        2 |
| 888777 | isabel betancur   | mujer  | 1977-11-15      |        1 |
| 999111 | veronica gonzalez | mujer  | 1982-03-30      |        1 |
+--------+-------------------+--------+-----------------+----------+
11 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT COUNT(*) AS total_hombres_mayores_30_mas1hijo
    -> FROM Repazo2
    -> WHERE sexo = 'hombre'
    ->   AND SUBSTR(fechanacimiento,1,4) <= '1980'
    ->   AND nrohijos > 1;
+-----------------------------------+
| total_hombres_mayores_30_mas1hijo |
+-----------------------------------+
|                                 2 |
+-----------------------------------+
1 row in set (0,001 sec)

MariaDB [Fechas]> SELECT * FROM Repazo2;
+--------+-------------------+--------+-----------------+----------+
| codigo | nombre            | sexo   | fechanacimiento | nrohijos |
+--------+-------------------+--------+-----------------+----------+
| 111222 | carlos ramirez    | hombre | 1969-04-04      |        2 |
| 111333 | andrea gutierrez  | mujer  | 1985-04-12      |        1 |
| 333666 | marina ruiz       | mujer  | 1978-12-15      |        3 |
| 333777 | gladys bermudez   | mujer  | 1979-01-01      |        2 |
| 444666 | sandra henao      | mujer  | 1982-11-25      |        3 |
| 444777 | carlos sepulveda  | hombre | 1974-01-10      |        1 |
| 555333 | fernando perez    | hombre | 1980-11-11      |        4 |
| 555777 | mario gomez       | hombre | 1982-05-29      |        2 |
| 666555 | juliana arredondo | mujer  | 1988-12-31      |        2 |
| 888777 | isabel betancur   | mujer  | 1977-11-15      |        1 |
| 999111 | veronica gonzalez | mujer  | 1982-03-30      |        1 |
+--------+-------------------+--------+-----------------+----------+
11 rows in set (0,001 sec)

MariaDB [Fechas]> SELECT COUNT(*) AS total_mujeres_mayores_25_mas1hijo FROM Repazo2 WHERE sexo = 'mujer' AND SUBSTR(fechanacimiento,1,4) <= '1985' AND nrohijos <=3;
+-----------------------------------+
| total_mujeres_mayores_25_mas1hijo |
+-----------------------------------+
|                                 6 |
+-----------------------------------+
1 row in set (0,001 sec)

MariaDB [Fechas]> SELECT CURDATE() AS fecha_sistema;
+---------------+
| fecha_sistema |
+---------------+
| 2025-09-12    |
+---------------+
1 row in set (0,000 sec)

MariaDB [Fechas]> SELECT CURTIME() AS hora_sistema;
+--------------+
| hora_sistema |
+--------------+
| 16:05:01     |
+--------------+
1 row in set (0,000 sec)

MariaDB [Fechas]> notee;