This topic for those who are very beginner of SQL. Here
I will show some basic SQL by Microsoft SQL Server.
1.
Create a table: Here I created a table name hrm_employee. Here emp_gid is int type,
primary key and identity. Identity means its value will increment automatically
by the sql server. You don’t need to insert it’s value.
--Create Table : hrm_employee---
CREATE TABLE hrm_employee
(
emp_gid INT PRIMARY KEY IDENTITY,
emp_fullnm VARCHAR(100),
emp_nicknm VARCHAR(50),
emp_designation VARCHAR(100)
)
2.
Insert data in hrm_employee table: In this occasion, I have inserted 3 data i.e 3 rows.
If you see in closer look, you will see that I didn’t insert any value of
emp_gid because it increments its value automatically because it is an identity
column.
---Insert data ito table: hrm_employee----
-- Insert data i.e. row-1 ---
INSERT INTO hrm_employee
(
emp_fullnm
, emp_nicknm
, emp_designation
)
VALUES
(
'Md. Mahedee Hasan'
, 'Mahedee'
, 'Senior Software Engineer'
)
-- Insert data i.e. row-2 ---
INSERT INTO hrm_employee
(
emp_fullnm
, emp_nicknm
, emp_designation
)
VALUES
(
'Md. Asrafuzzaman'
, 'Emon'
, 'Senior Software Engineer'
)
-- Insert data i.e. row-3 ---
INSERT INTO hrm_employee
(
emp_fullnm
, emp_nicknm
, emp_designation
)
VALUES
(
'Md. Khondakar Enamul Haque'
, 'Rony'
, 'Broadcast Engineer'
)
4. Infromation
Retrive: Get all information of hrm_employee.
Here I showed two ways to retrive data and I suggest to use second one. Second
one is best practiced.
--Get all data from hrm_employee--
SELECT * FROM hrm_employee
--or
SELECT emp_gid, emp_fullnm,
emp_nicknm, emp_designation FROM hrm_employee
5. Update hrm_employee: Is very easy to update a row or multiple rows against
a condition. Lets look on the following query.
--update data from table: hrm_employee --
UPDATE hrm_employee
SET emp_fullnm = 'M.K. Enamul Haque'
, emp_designation = 'Senior Broadcast Engineer'
WHERE emp_gid = 3
6. Delete
Information: If you want to delete information
from hrm_employee against a condition follow the query.
---Delete data from table: hrm_employee---
DELETE FROM hrm_employee WHERE
emp_gid = 3
7. Drop Table: Drop table means remove table for database. Use the
query to drop hrm_employee table.
---Drop table i.e remove table from Database--
DROP TABLE hrm_employee
