SQL query is used to retrieve selected row or column from the database based on the given condition . It is also used to retrieve data from a table in database .
Syntax ->

 Select expression from table_Name where clause ;  // Expression indicate that column , which we want to retrieve 

Optional Clause in Select Statement
Where clause -> Using this clause we can retrieve specified rows or columns .
Group By clause -> It is used to Group the elements and arranged them based on the specified condition and get the aggregate result .
Having clause -> It is used to select the group which come from the Group By clause .
Order By clause -> Used to get the data from which order either by increasing or decreasing .

**Student_name**       **Student_Age**      **Student_Id**
   Mukesh                  23                       1
    Ayush                  24                       2
    Ravi                   25                       3

Now , Suppose you want to select all the name from table student

Select student_name from student ; // sql is not case sensitive so Select can be select also 

Output -> Mukesh Ayush Ravi
Now if you want to select student age also then

select Student_name , Student_Age from student ; 

Now if you want to select any specified column then you can do with the clauses i.e where , Group By , Having ect .