mysql> create database if not exists examen;
Query OK, 1 row affected (0.01 sec)


mysql> create table persona (
    -> id int auto_increment,
    -> nombre varchar(30),
    -> edad int,
    -> key (id),
    -> primary key (id));
Query OK, 0 rows affected (0.05 sec)

mysql> desc persona;
+--------+-------------+------+-----+---------+----------------+
| Field  | Type        | Null | Key | Default | Extra          |
+--------+-------------+------+-----+---------+----------------+
| id     | int(11)     | NO   | PRI | NULL    | auto_increment |
| nombre | varchar(30) | YES  |     | NULL    |                |
| edad   | int(11)     | YES  |     | NULL    |                |
+--------+-------------+------+-----+---------+----------------+
3 rows in set (0.07 sec)



mysql> alter table persona add ap_pat varchar(200);
Query OK, 0 rows affected (0.21 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc persona;
+--------+--------------+------+-----+---------+----------------+
| Field  | Type         | Null | Key | Default | Extra          |
+--------+--------------+------+-----+---------+----------------+
| id     | int(11)      | NO   | PRI | NULL    | auto_increment |
| nombre | varchar(30)  | YES  |     | NULL    |                |
| edad   | int(11)      | YES  |     | NULL    |                |
| ap_pat | varchar(200) | YES  |     | NULL    |                |
+--------+--------------+------+-----+---------+----------------+
4 rows in set (0.02 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('cesar', 'celis', nu
ll, 21);
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('luisa', 'mondragon'
, null, 18);
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('pedro', 'solis', nu
ll, 18);
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('alberto', 'castella
nos', null, 27);
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('josue', 'larios', n
ull, 17);
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('andres', 'sanches',
 null, 22);
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('leslie', 'ramirez',
 null, 20);
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('claudia', 'zamora',
 null, 29);
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('leticia', 'sanches'
, null, 25);
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona(nombre, ap_pat, id, edad) values('jose', 'garcia', nu
ll, 18);
Query OK, 1 row affected (0.00 sec)

mysql> select * from persona;
+----+---------+------+-------------+
| id | nombre  | edad | ap_pat      |
+----+---------+------+-------------+
|  1 | cesar   |   21 | celis       |
|  2 | luisa   |   18 | mondragon   |
|  3 | pedro   |   18 | solis       |
|  4 | alberto |   27 | castellanos |
|  5 | josue   |   17 | larios      |
|  6 | andres  |   22 | sanches     |
|  7 | leslie  |   20 | ramirez     |
|  8 | claudia |   29 | zamora      |
|  9 | leticia |   25 | sanches     |
| 10 | jose    |   18 | garcia      |
+----+---------+------+-------------+
10 rows in set (0.00 sec)


mysql> insert into persona values(null, 'andrea', 23, 'lopez');
Query OK, 1 row affected (0.01 sec)

mysql> insert into persona values(null, 'roberto', 37, 'alanis');
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona values(null, 'jose', 22, 'garcia');
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona values(null, 'marisol', 21, 'flores');
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona values(null, 'salvador', 21, 'morales');
Query OK, 1 row affected (0.01 sec)

mysql> insert into persona values(null, 'claudia', 21, 'peralta');
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona values(null, 'miriam', 26, 'hernandez');
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona values(null, 'julia', 19, 'hernandez');
Query OK, 1 row affected (0.01 sec)

mysql> insert into persona values(null, 'guillermo', 23, 'ramirez');
Query OK, 1 row affected (0.00 sec)

mysql> insert into persona values(null, 'jose', 20, 'sanches');
Query OK, 1 row affected (0.00 sec)

mysql> select * from persona;
+----+-----------+------+-------------+
| id | nombre    | edad | ap_pat      |
+----+-----------+------+-------------+
|  1 | cesar     |   21 | celis       |
|  2 | luisa     |   18 | mondragon   |
|  3 | pedro     |   18 | solis       |
|  4 | alberto   |   27 | castellanos |
|  5 | josue     |   17 | larios      |
|  6 | andres    |   22 | sanches     |
|  7 | leslie    |   20 | ramirez     |
|  8 | claudia   |   29 | zamora      |
|  9 | leticia   |   25 | sanches     |
| 10 | jose      |   18 | garcia      |
| 11 | andrea    |   23 | lopez       |
| 12 | roberto   |   37 | alanis      |
| 13 | jose      |   22 | garcia      |
| 14 | marisol   |   21 | flores      |
| 15 | salvador  |   21 | morales     |
| 16 | claudia   |   21 | peralta     |
| 17 | miriam    |   26 | hernandez   |
| 18 | julia     |   19 | hernandez   |
| 19 | guillermo |   23 | ramirez     |
| 20 | jose      |   20 | sanches     |
+----+-----------+------+-------------+
20 rows in set (0.00 sec)

mysql> create table salario(
    -> id_persona int,
    -> salario decimal(6,2),
    -> puesto varchar(200),
    -> key (id_persona),
    -> foreign key (id_persona) references persona (id));
Query OK, 0 rows affected (0.07 sec)

mysql> desc salario;
+------------+--------------+------+-----+---------+-------+
| Field      | Type         | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------+
| id_persona | int(11)      | YES  | MUL | NULL    |       |
| salario    | decimal(6,2) | YES  |     | NULL    |       |
| puesto     | varchar(200) | YES  |     | NULL    |       |
+------------+--------------+------+-----+---------+-------+
3 rows in set (0.03 sec)

mysql> alter table persona drop edad;
Query OK, 0 rows affected (0.20 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> select * from persona;
+----+-----------+-------------+
| id | nombre    | ap_pat      |
+----+-----------+-------------+
|  1 | cesar     | celis       |
|  2 | luisa     | mondragon   |
|  3 | pedro     | solis       |
|  4 | alberto   | castellanos |
|  5 | josue     | larios      |
|  6 | andres    | sanches     |
|  7 | leslie    | ramirez     |
|  8 | claudia   | zamora      |
|  9 | leticia   | sanches     |
| 10 | jose      | garcia      |
| 11 | andrea    | lopez       |
| 12 | roberto   | alanis      |
| 13 | jose      | garcia      |
| 14 | marisol   | flores      |
| 15 | salvador  | morales     |
| 16 | claudia   | peralta     |
| 17 | miriam    | hernandez   |
| 18 | julia     | hernandez   |
| 19 | guillermo | ramirez     |
| 20 | jose      | sanches     |
+----+-----------+-------------+
20 rows in set (0.00 sec)

mysql> alter table salario change puesto puesto_persona varchar(200);
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc salario;
+----------------+--------------+------+-----+---------+-------+
| Field          | Type         | Null | Key | Default | Extra |
+----------------+--------------+------+-----+---------+-------+
| id_persona     | int(11)      | YES  | MUL | NULL    |       |
| salario        | decimal(6,2) | YES  |     | NULL    |       |
| puesto_persona | varchar(200) | YES  |     | NULL    |       |
+----------------+--------------+------+-----+---------+-------+
3 rows in set (0.01 sec)

mysql> alter table salario change salario salario_persona int not null;
Query OK, 0 rows affected (0.15 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc salario;
+-----------------+--------------+------+-----+---------+-------+
| Field           | Type         | Null | Key | Default | Extra |
+-----------------+--------------+------+-----+---------+-------+
| id_persona      | int(11)      | YES  | MUL | NULL    |       |
| salario_persona | int(11)      | NO   |     | NULL    |       |
| puesto_persona  | varchar(200) | YES  |     | NULL    |       |
+-----------------+--------------+------+-----+---------+-------+
3 rows in set (0.02 sec)

mysql> insert into salario values(1, 5000, 'tecnico');
Query OK, 1 row affected (0.02 sec)

mysql> insert into salario values(2, 11000, 'programador');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(3, 4000, 'intendencia');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(4, 12500, 'contador');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(5, 6500, 'tecnico');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(6, 6500, 'tecnico');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(7, 9700, 'ingeniero');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(8, 14250, 'ingeniero');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(9, 8800, 'vendedor');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(10, 4400, 'mensajero');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(11, 6000, 'soporte tecnico');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(12, 17500, 'gerente');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(13, 4950, 'almacenista');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(14, 5350, 'secretaria');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(15, 4350, 'empacador');
Query OK, 1 row affected (0.01 sec)

mysql> insert into salario values(16, 6000, 'secretaria');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(17, 6200, 'tecnico');
Query OK, 1 row affected (0.01 sec)

mysql> insert into salario values(18, 10500, 'administrador');
Query OK, 1 row affected (0.01 sec)

mysql> insert into salario values(19, 7000, 'tecnico');
Query OK, 1 row affected (0.00 sec)

mysql> insert into salario values(20, 13000, 'ingeniero');
Query OK, 1 row affected (0.02 sec)


mysql> select * from salario;
+------------+-----------------+-----------------+
| id_persona | salario_persona | puesto_persona  |
+------------+-----------------+-----------------+
|          1 |            5000 | tecnico         |
|          2 |           11000 | programador     |
|          3 |            4000 | intendencia     |
|          4 |           12500 | contador        |
|          5 |            6500 | tecnico         |
|          6 |            6500 | tecnico         |
|          7 |            9700 | ingeniero       |
|          8 |           14250 | ingeniero       |
|          9 |            8800 | vendedor        |
|         10 |            4400 | mensajero       |
|         11 |            6000 | soporte tecnico |
|         12 |           17500 | gerente         |
|         13 |            4950 | almacenista     |
|         14 |            5350 | secretaria      |
|         15 |            4350 | empacador       |
|         16 |            6000 | secretaria      |
|         17 |            6200 | tecnico         |
|         18 |           10500 | administrador   |
|         19 |            7000 | tecnico         |
|         20 |           13000 | ingeniero       |
+------------+-----------------+-----------------+
20 rows in set (0.00 sec)


mysql> alter table salario drop puesto_persona;
Query OK, 0 rows affected (0.11 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> select * from salario;
+------------+-----------------+
| id_persona | salario_persona |
+------------+-----------------+
|          1 |            5000 |
|          2 |           11000 |
|          3 |            4000 |
|          4 |           12500 |
|          5 |            6500 |
|          6 |            6500 |
|          7 |            9700 |
|          8 |           14250 |
|          9 |            8800 |
|         10 |            4400 |
|         11 |            6000 |
|         12 |           17500 |
|         13 |            4950 |
|         14 |            5350 |
|         15 |            4350 |
|         16 |            6000 |
|         17 |            6200 |
|         18 |           10500 |
|         19 |            7000 |
|         20 |           13000 |
+------------+-----------------+
20 rows in set (0.00 sec)


mysql> alter table persona add edad int null default 21;
Query OK, 0 rows affected (0.13 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> select * from persona;
+----+-----------+-------------+------+
| id | nombre    | ap_pat      | edad |
+----+-----------+-------------+------+
|  1 | cesar     | celis       |   21 |
|  2 | luisa     | mondragon   |   21 |
|  3 | pedro     | solis       |   21 |
|  4 | alberto   | castellanos |   21 |
|  5 | josue     | larios      |   21 |
|  6 | andres    | sanches     |   21 |
|  7 | leslie    | ramirez     |   21 |
|  8 | claudia   | zamora      |   21 |
|  9 | leticia   | sanches     |   21 |
| 10 | jose      | garcia      |   21 |
| 11 | andrea    | lopez       |   21 |
| 12 | roberto   | alanis      |   21 |
| 13 | jose      | garcia      |   21 |
| 14 | marisol   | flores      |   21 |
| 15 | salvador  | morales     |   21 |
| 16 | claudia   | peralta     |   21 |
| 17 | miriam    | hernandez   |   21 |
| 18 | julia     | hernandez   |   21 |
| 19 | guillermo | ramirez     |   21 |
| 20 | jose      | sanches     |   21 |
+----+-----------+-------------+------+
20 rows in set (0.00 sec)

mysql> alter table persona add sexo enum('M','F') default 'M';
Query OK, 0 rows affected (0.12 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> select * from persona;
+----+-----------+-------------+------+------+
| id | nombre    | ap_pat      | edad | sexo |
+----+-----------+-------------+------+------+
|  1 | cesar     | celis       |   21 | M    |
|  2 | luisa     | mondragon   |   21 | M    |
|  3 | pedro     | solis       |   21 | M    |
|  4 | alberto   | castellanos |   21 | M    |
|  5 | josue     | larios      |   21 | M    |
|  6 | andres    | sanches     |   21 | M    |
|  7 | leslie    | ramirez     |   21 | M    |
|  8 | claudia   | zamora      |   21 | M    |
|  9 | leticia   | sanches     |   21 | M    |
| 10 | jose      | garcia      |   21 | M    |
| 11 | andrea    | lopez       |   21 | M    |
| 12 | roberto   | alanis      |   21 | M    |
| 13 | jose      | garcia      |   21 | M    |
| 14 | marisol   | flores      |   21 | M    |
| 15 | salvador  | morales     |   21 | M    |
| 16 | claudia   | peralta     |   21 | M    |
| 17 | miriam    | hernandez   |   21 | M    |
| 18 | julia     | hernandez   |   21 | M    |
| 19 | guillermo | ramirez     |   21 | M    |
| 20 | jose      | sanches     |   21 | M    |
+----+-----------+-------------+------+------+
20 rows in set (0.00 sec)

mysql> update persona set nombre = 'nallely', ap_pat = 'najera' where id = 1;
Query OK, 1 row affected (0.08 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set nombre = 'monica', ap_pat = 'avila' where id = 2;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set nombre = 'monserrat', ap_pat = 'zendejas' where id = 3
;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set nombre = 'carmen', ap_pat = 'islas' where id = 4;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 26 where id = 1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 22 where id = 2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 31 where id = 3;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 25 where id = 4;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 40 where id = 5;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 37 where id = 6;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 27 where id = 7;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 28 where id = 8;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 19 where id = 9;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 21 where id = 10;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 1  Changed: 0  Warnings: 0

mysql> update persona set edad = 29 where id = 11;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 31 where id = 12;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 33 where id = 13;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 20 where id = 14;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 22 where id = 15;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 26 where id = 16;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 35 where id = 17;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 19 where id = 18;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 24 where id = 19;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set edad = 21 where id = 20;
Query OK, 0 rows affected (0.01 sec)
Rows matched: 1  Changed: 0  Warnings: 0

mysql> update persona set sexo = 'F' where sexo = 'M' limit 4;
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3  Changed: 3  Warnings: 0

mysql> update persona set sexo = 'F' where id > 6 limit 3;
Query OK, 3 rows affected (0.01 sec)
Rows matched: 3  Changed: 3  Warnings: 0

mysql> update persona set sexo = 'F' where id = 11;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set sexo = 'F' where id = 14;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update persona set sexo = 'F' where id > 15 limit 3;
Query OK, 3 rows affected (0.01 sec)
Rows matched: 3  Changed: 3  Warnings: 0

mysql> select * from persona
    -> ;
+----+-----------+-----------+------+------+
| id | nombre    | ap_pat    | edad | sexo |
+----+-----------+-----------+------+------+
|  1 | nallely   | najera    |   26 | F    |
|  2 | monica    | avila     |   22 | F    |
|  3 | monserrat | zendejas  |   31 | F    |
|  4 | carmen    | islas     |   25 | F    |
|  5 | josue     | larios    |   40 | M    |
|  6 | andres    | sanches   |   37 | M    |
|  7 | leslie    | ramirez   |   27 | F    |
|  8 | claudia   | zamora    |   28 | F    |
|  9 | leticia   | sanches   |   19 | F    |
| 10 | jose      | garcia    |   21 | M    |
| 11 | andrea    | lopez     |   29 | F    |
| 12 | roberto   | alanis    |   31 | M    |
| 13 | jose      | garcia    |   33 | M    |
| 14 | marisol   | flores    |   20 | F    |
| 15 | salvador  | morales   |   22 | M    |
| 16 | claudia   | peralta   |   26 | F    |
| 17 | miriam    | hernandez |   35 | F    |
| 18 | julia     | hernandez |   19 | F    |
| 19 | guillermo | ramirez   |   24 | M    |
| 20 | jose      | sanches   |   21 | M    |
+----+-----------+-----------+------+------+
20 rows in set (0.00 sec)

mysql> select nombre, ap_pat, edad, sexo from persona;
+-----------+-----------+------+------+
| nombre    | ap_pat    | edad | sexo |
+-----------+-----------+------+------+
| nallely   | najera    |   26 | F    |
| monica    | avila     |   22 | F    |
| monserrat | zendejas  |   31 | F    |
| carmen    | islas     |   25 | F    |
| josue     | larios    |   40 | M    |
| andres    | sanches   |   37 | M    |
| leslie    | ramirez   |   27 | F    |
| claudia   | zamora    |   28 | F    |
| leticia   | sanches   |   19 | F    |
| jose      | garcia    |   21 | M    |
| andrea    | lopez     |   29 | F    |
| roberto   | alanis    |   31 | M    |
| jose      | garcia    |   33 | M    |
| marisol   | flores    |   20 | F    |
| salvador  | morales   |   22 | M    |
| claudia   | peralta   |   26 | F    |
| miriam    | hernandez |   35 | F    |
| julia     | hernandez |   19 | F    |
| guillermo | ramirez   |   24 | M    |
| jose      | sanches   |   21 | M    |
+-----------+-----------+------+------+
20 rows in set (0.00 sec)

mysql> select nombre, edad from persona where sexo = 'M';
+-----------+------+
| nombre    | edad |
+-----------+------+
| josue     |   40 |
| andres    |   37 |
| jose      |   21 |
| roberto   |   31 |
| jose      |   33 |
| salvador  |   22 |
| guillermo |   24 |
| jose      |   21 |
+-----------+------+
8 rows in set (0.00 sec)

mysql> select nombre, edad from persona where sexo = 'F';
+-----------+------+
| nombre    | edad |
+-----------+------+
| nallely   |   26 |
| monica    |   22 |
| monserrat |   31 |
| carmen    |   25 |
| leslie    |   27 |
| claudia   |   28 |
| leticia   |   19 |
| andrea    |   29 |
| marisol   |   20 |
| claudia   |   26 |
| miriam    |   35 |
| julia     |   19 |
+-----------+------+
12 rows in set (0.00 sec)

mysql> select sexo, count('id') cuantos from persona group by sexo;
+------+---------+
| sexo | cuantos |
+------+---------+
| M    |       8 |
| F    |      12 |
+------+---------+
2 rows in set (0.00 sec)

mysql> select avg(edad) promedio_edad, count('id') cuantos, sexo from persona gr
oup by sexo;
+---------------+---------+------+
| promedio_edad | cuantos | sexo |
+---------------+---------+------+
|       28.6250 |       8 | M    |
|       25.5833 |      12 | F    |
+---------------+---------+------+
2 rows in set (0.00 sec)

mysql> select count(id) 'menores de 21', sexo from persona where edad < 22 group
 by sexo;
+---------------+------+
| menores de 21 | sexo |
+---------------+------+
|             2 | M    |
|             3 | F    |
+---------------+------+
2 rows in set (0.00 sec)



C:\Program Files\MySQL\MySQL Server 5.6\bin>mysqldump -p -u root examen > C:\Use
rs\Batcaver\examen.sql
Enter password: *********

C:\Program Files\MySQL\MySQL Server 5.6\bin>