Taller Valores Negativos
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| autoincremento |
| cdcol |
| colegio |
| libreria |
| mysql |
| performance_schema |
| phpmyadmin |
| test |
| webauth |
+--------------------+
10 rows in set (0.00 sec)
mysql> create database precios;
Query OK, 1 row affected (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| autoincremento |
| cdcol |
| colegio |
| libreria |
| mysql |
| performance_schema |
| phpmyadmin |
| precios |
| test |
| webauth |
+--------------------+
11 rows in set (0.00 sec)
mysql> use precios;
Database changed
mysql> show tables;
Empty set (0.00 sec)
mysql> use precios;
Database changed
mysql> show tables;
Empty set (0.00 sec)
mysql> use precios;
Database changed
mysql> create table producto
-> (codigo int auto_increment not null primary key,
-> nombre char(10) not null,
-> precio float not null);
Query OK, 0 rows affected (0.20 sec)
mysql> show tables;
+-------------------+
| Tables_in_precios |
+-------------------+
| producto |
+-------------------+
1 row in set (0.00 sec)
mysql> describe producto;
+--------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------+----------+------+-----+---------+----------------+
| codigo | int(11) | NO | PRI | NULL | auto_increment |
| nombre | char(10) | NO | | NULL | |
| precio | float | NO | | NULL | |
+--------+----------+------+-----+---------+----------------+
3 rows in set (0.00 sec)
mysql> insert into producto(nombre,precio) values ('camisa',25000);
Query OK, 1 row affected (0.05 sec)
mysql> insert into producto(nombre,precio) values ('pantalon',45000);
Query OK, 1 row affected (0.05 sec)
mysql> insert into producto(nombre,precio) values ('chaqueta',-100000);
Query OK, 1 row affected (0.03 sec)
mysql> select * from producto;
+--------+----------+---------+
| codigo | nombre | precio |
+--------+----------+---------+
| 1 | camisa | 25000 |
| 2 | pantalon | 45000 |
| 3 | chaqueta | -100000 |
+--------+----------+---------+
3 rows in set (0.00 sec)
mysql> alter table producto modify precio float unsigned not null;
Query OK, 3 rows affected, 1 warning (0.62 sec)
Records: 3 Duplicates: 0 Warnings: 1
mysql> select * from producto;
+--------+----------+--------+
| codigo | nombre | precio |
+--------+----------+--------+
| 1 | camisa | 25000 |
| 2 | pantalon | 45000 |
| 3 | chaqueta | 0 |
+--------+----------+--------+
3 rows in set (0.00 sec)
mysql> update producto set precio=100000 where codigo=3;
Query OK, 1 row affected (0.05 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from producto;
+--------+----------+--------+
| codigo | nombre | precio |
+--------+----------+--------+
| 1 | camisa | 25000 |
| 2 | pantalon | 45000 |
| 3 | chaqueta | 100000 |
+--------+----------+--------+
3 rows in set (0.00 sec)
mysql> exit