MySQL basic commands _ MySQL

The following describes the basic MySQL commands.

1. start the MySQL server
In fact, the previous article describes how to start MySQL. Two methods: one is to use winmysqladmin. if the machine runs automatically at startup, you can directly go to the next step. Second, run c: mysqlinmysqld in DOS mode
2. enter the mysql interactive operation interface
Run: d: mysqlbinmysql in DOS mode
The prompt "mysql" appears. the interactive mysql operation mode is displayed.
If "ERROR 2003: Can't connect to MySQL server on 'localhost' (10061)" appears,
It indicates that your MySQL instance has not been started yet.
3. exit the MySQL operation interface.
Enter quit at the mysql> prompt to exit the interactive operation interface at any time:
Mysql> quit
Bye
You can also use control-D to exit.
4. the First Command
Mysql> select version (), current_date ();
+ ---------------- + ----------------- +
| Version () | current_date () |
+ ---------------- + ----------------- +
| 3.23.25a-debug | 2001-05-17 |
+ ---------------- + ----------------- +
1 row in set (0.01 sec)
Mysql>
This command requires the mysql server to tell you its version number and current date. Run the preceding command in different cases to check the result. The results show that the case sensitivity of the mysql command is consistent.
Perform the following operations:
Mysql> Select (20 + 5) * 4;
Mysql> Select (20 + 5) * 4, sin (pi ()/3 );
Mysql> Select (20 + 5) * 4 AS Result, sin (pi ()/3); (AS: specify the alias AS Result)
5. multi-line statements
A command can be input in multiple lines until the semicolon ";" is displayed:

Mysql> select
-> USER ()
->,
-> Now ()
->;
+ -------------------- + --------------------- +
| USER () | now () |
+ -------------------- + --------------------- +
| ODBC @ localhost | 22:59:15 |
+ -------------------- + --------------------- +
1 row in set (0.06 sec)
Mysql>
Note how to use the comma in the middle and the last semicolon.
6. multiple commands in one line
Run the following command:
Mysql> select user (); select now ();
+ ------------------ +
| USER () |
+ ------------------ +
| ODBC @ localhost |
+ ------------------ +
1 row in set (0.00 sec)
+ --------------------- +
| NOW () |
+ --------------------- +
| 23:06:15 |
+ --------------------- +
1 row in set (0.00 sec)
Mysql>
Note the semicolons in the middle. commands are separated by semicolons.
7. display the existing database
Mysql> show databases;
+ ---------- +
| Database |
+ ---------- +
| Mysql |
| Test |
+ ---------- +
2 row in set (0.06 sec)
Mysql>
8. select a database and display the selected database
Mysql> USE mysql
Database changed
Mysql>
(USE and QUIT commands do not need to end with a semicolon .)
Mysql> select database ();
+ --------------- +
| Database () |
+ --------------- +
| Mysql |
+ --------------- +
1 row in set (0.00 sec)
9. display tables in the current database
Mysql> show tables;
10. display the table (db) content
Mysql> select * from db;
11. command cancellation
When the command input is wrong and cannot be changed (multi-line statement), you can use c to cancel the command before the semicolon appears.
Mysql> select
-> User ()
-> C
Mysql>
This is some of the most commonly used basic operation commands. you can stick to it after multiple exercises.