MySQL for Beginners

A MySQL database server contains many databases (or schemas). Each database consists of one or more tables. A table is made up of columns (or fields) and rows (records).

The SQL keywords and commands are NOT case-sensitive. For clarity, they are shown in uppercase. The names or identifiers (database names, table names, column names, etc.) are case-sensitive in some systems, but not in other systems. Hence, it is best to treat identifiers as case-sensitive.

You can use SHOW DATABASES to list all the existing databases in the server.

mysql> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.00 sec)

The databases "mysql", "information_schema" and  "performance_schema" are system 

databases used internally by MySQL. A "test" database is  provided during 

installation for your testing. 

Creating and Deleting a Database - CREATE DATABASE and DROP DATABASE

You can create a new database using SQL command "CREATE DATABASE databaseName"; and delete a database using "DROP DATABASE databaseName". You could optionally apply condition "IF EXISTS" or "IF NOT EXISTS" to these commands. For example,

mysql> CREATE DATABASE south;
Query OK, 1 row affected (0.03 sec)
   
mysql> DROP DATABASE south;
Query OK, 0 rows affected (0.11 sec)
   
mysql> CREATE DATABASE IF NOT EXISTS south;
Query OK, 1 row affected (0.01 sec)
   
mysql> DROP DATABASE IF EXISTS south;
Query OK, 0 rows affected (0.00 sec)

IMPORTANT: Use SQL DROP (and DELETE) commands with extreme care, as the deleted entities are irrecoverable. THERE IS NO UNDO!!!