How to Use COUNT and GROUP BY Correctly in SQL

The Count(*) function is an aggregate function in SQL. You can find Count value from your SQL statement.

How to use SQL Count function

Count(*) means, the count value of fields in a Table. In this post, I will explain my results on how to use COUNT(*) and GROUP BY.

SQL Count Aggregate function

In this post, I am creating a Table and I will insert rows. Then I get data from the Table using Count Function.

If you do not use the SQL query correctly, you will not get the correct result.

Steps that I followed to use Count function

Step:1 to enter data into a Table

S.NO	Student Name	Country Name
1	Ramani	USA
2	Krishna	Japan
3	Mani	UK
4	Rani	India

Step: 2 To create a Table using SQL query

create table 
counttable(sno integer,
student_name varchar(20),
country_name char(20));

Step: 3 SQL query to check Table created or not

desc counttable;

Table “desc” result

sno int(11) YES NULL 
student_name varchar(20) YES NULL 
country_name char(20) YES NULL 

Also Read: What is aggregate function by dofactory

Step: 4 SQL Query to Insert values into a Table

insert into counttable values
(1, 'Ramani', 'USA');
insert into counttable values
(
2, 'Krishan', 'Japan'
);
insert into counttable values
(
3, 'Mani', 'UK'
);
insert into counttable values
(
4, 'Rani', 'India'
);

SQL Result after inserting values

1 Ramani USA 
2 Krishan Japan 
3 Mani UK 
4 Rani India 

Step: 5 SQL Query “Count function” with Group By and Order By

An SQL query to find a student who studied in the USA by using SQL Count Group by

select student_name, count(*)
from counttable
where country_name = 'USA'
group by student_name
order by student_name;

Group By student_name command allows for the Aggregates to be calculated per student_name.

The data has also been sorted with the ORDER BY statement.

Result of SQL Count (*)

Ramani 1

The important point is the non-aggregate field in SELECT statement requires GROUP BY. The ORDER BY will sort the result. If you do not want sort, you no need to use in your SQL.

Related Posts

• 8 Top String Functions Useful to Write SQL Queries Smartly
• The Order of SQL Query Execution Read Today
• Sample SQL ALTER queries useful for your project
• SQL Query top methods to Sort the output
• Where Condition ideas to use in SQL query