MySQL

mysql> SHOW databases;
+--------------------+
| Database                |
+--------------------+
| information_schema  |
| mysql                     |
| tcdb                       |
| test                        |
| webserver              |
| wordpress              |
| xedb                      |
+--------------------+
7 rows in set (0.07 sec)

mysql> USE test;
Database changed

mysql> CREATE TABLE student(
    -> no int,
    -> name varchar(10),
    -> city varchar(10),
    -> email varchar(20)
    -> );
Query OK, 0 rows affected (0.00 sec)

 

mysql> INSERT INTO student(no, name, ciry) value (1, 'aaa','Seoul');
ERROR 1054 (42S22): Unknown column 'ciry' in 'field list'
mysql> INSERT INTO student(no, name, city) value (1, 'aaa','Seoul');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO student(no, name, city) value (2, 'bbb','Busan');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO student(no, name, city) value (3, 'ccc','Daegu');
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO student(no, name, city) value (4, 'ddd','Suwon');
Query OK, 1 row affected (0.00 sec)

 

mysql> SELECT * FROM student;
+------+------+-------+-------+
| no    | name | city     | email  |
+------+------+-------+-------+
|     1 | aaa    | Seoul | NULL   |
|     2 | bbb    | Busan| NULL   |
|     3 | ccc    | Daegu| NULL   |
|     4 | ddd    |Suwon| NULL   |
+------+------+-------+-------+
4 rows in set (0.00 sec)

 

 

mysql> UPDATE student SET email='aaa@abc.com' WHERE no=1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> SELECT * FROM student;
+------+------+-------+-------------+
| no    | name | city     | email           |
+------+------+-------+-------------+
|      1 | aaa   | Seoul | aaa@abc.com|
|      2 | bbb   | Busan| NULL            |
|      3 | ccc   | Daegu| NULL            |
|      4 | ddd   |Suwon| NULL            |
+------+------+-------+-------------+
4 rows in set (0.00 sec)

 

mysql> UPDATE student SET city='Busan' WHERE no='3';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

 

mysql> SELECT * FROM student;                      
+------+------+-------+---------------+
| no    | name | city     | email              |
+------+------+-------+---------------+
|      1 | aaa  | Seoul   | aaa@abc.com |
|      2 | bbb  | Busan  | NULL              |
|      3 | ccc  | Busan  | NULL              |
|      4 | ddd  | Suwon | NULL              |
+------+------+-------+---------------+
4 rows in set (0.00 sec)

 

mysql> SELECT no, name FROM student WHERE city='Busan';
+------+------+
| no    | name |
+------+------+
|      2 | bbb   |
|      3 | ccc   |
+------+------+
2 rows in set (0.01 sec)