Your First SQL statement :)

 Using Oracle Free SQL  , 

• Select HR schema to connect to all HR tables 
• Write simple query like this 👇

    SELECT *

    FROM HR.EMPLOYEES

• Press RUN button 
• you will get the result like this 👇

        

• you can select certain data like this 👇

    SELECT EMPLOYEE_ID , FIRST_NAME , LAST_NAME

    FROM HR.EMPLOYEES   

• you will get the result like this 👇

 

Explanation of code:

as you see EMPLOYEES table has many columns (data) , like

EMPLOYEE_ID, FIRST_NAME, LAST_NAME, EMAIL, PHONE_NUMBER, HIRE_DATE,

JOB_ID, SALARY, MANAGER_ID, DEPARTMENT_ID

you can select data by SELECT statement , the used SQL is simple one to get data from database

you can select data from one table , or many tables as will know later

you can get data as it is or format the result as well

you can filter data as needed as will know later

now , assume we need to get employees' full name ,

we can write SQL as this 👇 using symbol || which is the symbol to concatenate 2 string(character)

SELECT EMPLOYEE_ID , FIRST_NAME ||' '|| LAST_NAME   FULL_NAME

FROM HR.EMPLOYEES

as you see , we can set alias for the selected data , here FULL_NAME is called alias ,

which means a readable title for selected data

let's we need an alias with space like Hire Date , in this case we can use it inside "" and use AS clause as will see soon

now , we need to get full name , hire date in format of "dd Month yyyy" or any valid format , do you know how to get that ?

if you don't know ways to convert date to needed format , you can look at this help page

if you know how to format date , it is easy to write the SQL which will be

SELECT EMPLOYEE_ID , FIRST_NAME ||' '|| LAST_NAME   FULL_NAME

, TO_CHAR(HIRE_DATE,'DD Month YYYY')  as "Hire Date"

FROM HR.EMPLOYEES

here we use alias in 2 ways , just new title like FULL_NAME which is common used in programming ,

and new title with space like Hire Date , using as "Hire Date" , which is used for extract data to external files

the result will be like this 👇

this is how to write simple SQL statement, and in next post we will filter data using WHERE clause