 CREATE TABLE employees (
    employee_id INT PRIMARY KEY,
    first_name VARCHAR(50),
    last_name VARCHAR(50),
    department VARCHAR(50),
    salary INT,
    hire_date DATE
);

INSERT INTO employees (employee_id, first_name, last_name, department, salary, hire_date) VALUES
(1, 'John', 'Doe', 'IT', 60000, '2020-01-15'),
(2, 'Jane', 'Smith', 'HR', 55000, '2019-03-10'),
(3, 'Robert', 'Brown', 'IT', 70000, '2018-07-23'),
(4, 'Emily', 'Davis', 'Finance', 80000, '2021-06-01'),
(5, 'Michael', 'Wilson', 'HR', 45000, '2022-01-10');


select * from employees;

-- order by salary in ascending order.
select * from employees order by salary asc;

-- order by salary in descending order.
select * from employees order by salary desc;

-- wildcard:
select * from employees where first_name like "J_n_";


-- print all those last anmes that ends with n:
select * from employees where last_name like "%n";


select * from employees where hire_date like "____-01-____";

--  Select all employees and order them by their hire date in descending order.
Select * from employees order by hire_date desc;
 
-- Question: Select all employees whose first name ends with 'n' and sort them by salary in ascending order.
Select * from employees where first_name like "%n" order by salary asc;

created 5 months ago by Mohd Ismail

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About MySQL

MySQL is a open-source, free and very popular relational database management system which is developed, distributed and supported by Oracle corporation.

Key Features:

Open-source relational database management systems.
Reliable, very fast and easy to use database server.
Works on client-server model.
Highly Secure and Scalable
High Performance
High productivity as it uses stored procedures, triggers, views to write a highly productive code.
Supports large databases efficiently.
Supports many operating systems like Linux*,CentOS*, Solaris*,Ubuntu*,Windows*, MacOS*,FreeBSD* and others.

Syntax help

Commands

1. CREATE

CREATE TABLE table_name (
                column1 datatype,
                column2 datatype,
                ....);

Example

CREATE TABLE EMPLOYEE (
  empId INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  dept TEXT NOT NULL
);

2. ALTER

ALTER TABLE Table_name ADD column_name datatype;

Example

INSERT INTO EMPLOYEE VALUES (0001, 'Dave', 'Sales');

3. TRUNCATE

TRUNCATE table table_name;

4. DROP

DROP TABLE table_name;

5. RENAME

RENAME TABLE table_name1 to new_table_name1;

6. COMMENT

Single-Line Comments:

 --Line1;

Multi-Line comments:

   /* Line1,
   Line2 */

DML Commands

1. INSERT

INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...);

Note: Column names are optional.

Example

INSERT INTO EMPLOYEE VALUES (0001, 'Ava', 'Sales');

2. SELECT

SELECT column1, column2, ...
FROM table_name
[where condition];

Example

SELECT * FROM EMPLOYEE where dept ='sales';

3. UPDATE

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;

Example

UPDATE EMPLOYEE SET dept = 'Sales' WHERE empId='0001';

4. DELETE

DELETE FROM table_name where condition;

Example

DELETE from EMPLOYEE where empId='0001';

Indexes

1. CREATE INDEX

  CREATE INDEX index_name on table_name(column_name);

To Create Unique index:

  CREATE UNIQUE INDEX index_name on table_name(column_name);

2. DROP INDEX

DROP INDEX index_name ON table_name;

Views

1. Create a View

Creating a View:
CREATE VIEW View_name AS 
Query;

2. How to call view

SELECT * FROM View_name;

3. Altering a View

ALTER View View_name AS 
Query;

4. Deleting a View

DROP VIEW View_name;

Triggers

1. Create a Trigger

CREATE TRIGGER trigger_name trigger_time trigger_event
    ON tbl_name FOR EACH ROW [trigger_order] trigger_body
/* where
trigger_time: { BEFORE | AFTER }
trigger_event: { INSERT | UPDATE | DELETE }
trigger_order: { FOLLOWS | PRECEDES } */

2. Drop a Trigger

DROP TRIGGER [IF EXISTS] trigger_name;

Stored Procedures

1. Create a Stored Procedure

CREATE PROCEDURE sp_name(p1 datatype)
BEGIN
/*Stored procedure code*/
END;

2. How to call Stored procedure

CALL sp_name;

3. How to delete stored procedure

DROP PROCEDURE sp_name;

Joins

1. INNER JOIN

SELECT * FROM TABLE1 INNER JOIN TABLE2 where condition;

2. LEFT JOIN

SELECT * FROM TABLE1 LEFT JOIN TABLE2 ON condition;

3. RIGHT JOIN

SELECT * FROM TABLE1 RIGHT JOIN TABLE2 ON condition;

4. CROSS JOIN

SELECT select_list from TABLE1 CROSS JOIN TABLE2;