EV: MySQL Learning

Installation

Login MySQL from command line:

shell>mysql -h -P -u -p[password] [database]

Notes: no space between -p and password

Install/uninstall MySQL service in Windows

shell>mysqld --install MySQL55 --defaults-file="E:DataDatabaseMySQLmy.ini"

shell>mysqld --remove MySQL55

Start MySQL Server:

            Two ways:

            1. shell>mysqld --console

            2. net start MySQL55

Stop/shutdown MySQL Server:

            Two ways:

            1. shell>mysqladmin shutdown -u root -p

            2. net stop MySQL55

Starting Multiple MySQL Instances

            1. Make a copy of one data directory. Assume that the new data directory is C:mydata2

            2. Create two option files. For example, create one file named C:my-opts1.cnf that looks

    like this:

[mysqld]

datadir = C:/mydata1

port = 3307

Create a second file named C:my-opts2.cnf that looks like this:

[mysqld]

datadir = C:/mydata2

port = 3308

3. Use the --defaults-file option to start each server with its own option file:

C:> C:mysqlinmysqld --defaults-file=C:my-opts1.cnf

C:> C:mysqlinmysqld-debug --defaults-file=C:my-opts2.cnf

Each server starts in the foreground (no new prompt appears until the server

exits later), so you will need to issue those two commands in separate console

windows.

4. To shut down the servers, connect to each using the appropriate port number:

C:> C:mysqlinmysqladmin --port=3307 shutdown

C:> C:mysqlinmysqladmin --port=3308 shutdown

Syntax

; = g

G

c (terminate input, useful for statement of multiple lines )

Notes: Do NOT use comma at the end when invoking parameters

, --comments, #comments

"", '' (string delimiter)

(escape character)

delimiter // (delimiter $$)

Identifier quote: backtick (`) (equivalent of [] in sql server)

. or source: to run a script file

Data Types

date, datetime, timestamp, text

Statements

LIMIT: SELECT * FROM table_name ... ORDER BY ... LIMIT

JOIN

INNER/LEFT/RIGHT JOIN

SELECT * FROM t1 INNER/LEFT/RIGHT JOIN t2 ON t1.id = t2.id

FULL OUTER JOIN:

You can emulate FULL OUTER JOIN using UNION (from MySQL 4.0.0 on):

SELECT * FROM t1

LEFT JOIN t2 ON t1.id = t2.id

UNION

SELECT * FROM t1

RIGHT JOIN t2 ON t1.id = t2.id

CURSOR

IF ... THEN ... END IF;

LOOP

Variable

           

            declare i int default 100;

            1. Used within stored programs;

            2. All declarations must appear at the first portion in the nearest BEGIN/END block.

            3. Variable declarations must appear before cursor or handler declarations.

Assign a value to a user variable (@):

1. SET statement

SET @var_name = expr [, @var_name = expr] …

For SET, either = or := can be used as the assignment operator.

2. Other statements. In this case, the assignment operator must be := and not = because the latter is treated as the comparison operator = in non-SET statements.

            select @max := max(ID) from customer;

TRANSACTION

BEGIN … END

Restrictions and Limits

DB Objects

Table

Column data type

AUTO_INCREMENT (Identity column)

Constraint of column default value (the default value must be a constant; it cannot be a function or an expression.)

PRIMARY KEY (id) (PK)

SHOW INDEX FROM tbl_name

SHOW CREATE TABLE  tbl_name G

SHOW TABLE STATUS WHERE Name = 'xxx'

ALTER TABLE  tbl_name  ENGINE = innodb

Column

Constraint

Index

Trigger

View

Procedure

select * from mysql.proc WHERE specific_name='myproc' AND db='test';

select routine_schema, routine_name, routine_type, data_type, routine_definition

from information_schema.routines;

show create procedure test.myproc;

Function

System Objects

Commands

            use

            status

Function, variable or constant

SELECT current_date, current_time, now()

SELECT user();

SELECT database();

SELECT version();

SELECT LAST_INSERT_ID(); (equivalent of SCOPE_IDENTITY())

SELECT IF(), IFNULL()

SELECT table_name,engine FROM INFORMATION_SCHEMA.TABLES WHERE table_schema=DATABASE();

SHOW ENGINES;

SET storage_engine=MyISAM;

DESCRIBE (equivalent of sp_help)

sp_helptext

show databases;

show tables;

show warnings/errors;

warnings;

nowarning;

The manual on SHOW WARNINGS states that:

It shows nothing if the last statement used a table and generated no messages. (That is, a statement that uses a table but generates no messages clears the message list.)

Statements that do not use tables and do not generate messages have no effect on the message list.

Maintenance

backup/restore db

Shutdown

Slow Shutdown:

1. Log into mysql;

2. run command "SET GLOBAL innodb_fast_shutdown=0;"

3. exit from mysql, then run the shutdown command.

Data directory

Look up the directory using command: show variables like 'datadir';

Physical (Raw)

MyISAM - Copy db/table files

InnoDB -

Logical Backups

shell>mysqldump -u root -p db_name

User & Privilege

            User

            CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'mypass';

            DROP USER 'jeffrey'@'localhost';

Password

SET PASSWORD FOR 'root'@'localhost' = PASSWORD('newpwd');

shell>mysqladmin -u root -p[password] password

            Privilege

                        Tables: mysql.user/db/tables_priv/columns_priv

grant all privileges on mydb.* to me@localhost;

revoke all privileges on mydb.* from me@localhost;

Notes:

1. Database test is always available for access to any user.

2. It seems revoking *.* can not cancel privileges granted on mydb.*.

                        delete from user where user = 'me' and host=’localhost’;

                        Notes:

Actions directly applied to user table need “flush privileges” to refresh

cached memory.

Client Tool

MySQL Workbench

Snippets tool window

phpMyAdmin