njmaeff / web-108-sql-cheat-sheet

SQL Cheat Sheet

SQL Cheat Sheet

login into MySQL from terminal

mysql -u myUser -p

SHOW USERS

select User, Host from mysql.user;

CREATE USERS

CREATE USER 'newuser'@'localhost' IDENTIFIED BY 'password';

• localhost can be an ip-address bound to the client connecting or the wildcard % which means any remote address.

GRANT PRIVILEGES, Show Granted Privileges and Remove.

GRANT ALL PRIVILEGES ON myDB . myTable TO 'newuser'@'localhost';

• ALL is a mysql privilege type and is the most permissive. There are less permisive types available.
• myDB . myTable can be substituted for the wildcard * which matches any.

SHOW, DELETE & CREATE DATABASES & SELECT DATABASES

-- show databases
show databases;o

-- create database
create database myDB;


-- select database
use myDB;

-- delete database
drop database myDB;

CREATE a TABLE with Columns and their data types

use Library;
create table Books
(
    id       int auto_increment
        primary key,
    bookName varchar(50) not null
)
    collate = utf8mb4_unicode_ci;

-- show columns
describe Books;

SHOW, DELETE & DROP Tables

-- show tables
show tables;

-- delete tables

drop table Books;

Insert ROWS & RECORDS (single and multiple)

-- single
INSERT INTO Books (id, bookName) VALUES (1, 'How I Play Golf');

-- multiple
INSERT INTO Books (id, bookName) VALUES (1, 'How I Play Golf'), (2, 'Tiger Woods'), (3, 'Tiger Woods');

SELECT with the WHERE Clause

select * from Books where bookName = 'Tiger Woods';

SELECT with the WHERE Clause using a range

select * from Books where id between 1 and 2;

DELETE an individual ROW

delete from Books where id = 1;

UPDATE a ROW

update Books
set bookName = 'How I Play Golf - Tiger Woods'
where id = 1;

Add a New Column and Modify

-- add rating column
alter table Books
add column rating INT;

-- update row
update Books
set rating = 5
where id = 1;

Order by and use Distinct

select distinct bookName, rating from Books
order by bookName;

Concatenate Columns

select concat("BookName ", bookName, " rating ", rating) as "Description" from Books;

Select Distinct Rows

select distinct bookName, rating from Books;

use LIKE to Search

select bookName, rating 
from Books
where bookName like '%Tiger%';

Select using IN

select bookName, rating 
from Books
where rating in (4, 5);

Create & Remove Index

-- create an index
create index names
on Books (id, bookName);

-- remove an index
alter table Books
drop index names;

Create Two Tables Demonstrating a One-to-many Relationship

One customer, many transaction logs.

create table Customer
(
    id       int auto_increment
        primary key,
    fullName varchar(32) not null
)
    collate = utf8mb4_unicode_ci;

create table TransactionLog
(
    id       int auto_increment
        primary key,
    customerID int not null,
    bookID int not null,
    foreign key(customerID) references Customer(id),
    foreign key(bookID) references Books(id)
)
    collate = utf8mb4_unicode_ci;

Use Inner Join

Only return customers that have a transaction.

select Customer.fullName, TransactionLog.id
from Customer inner join TransactionLog 
on Customer.id = TransactionLog.customerID;

JOIN Multiple Tables

Return transactions and the associated book name

select Customer.fullName, TransactionLog.id, Books.bookName
from Customer inner join TransactionLog 
on Customer.id = TransactionLog.customerID
inner join Books on TransactionLog.BookID = Books.id;