SQL COUNT(), AVG() and SUM()

1. SQL COUNT() Function :
   The COUNT() function provides the number of rows that matches a specified condition.

   COUNT() Syntax –

   SELECT COUNT(column_name)
   FROM table_name
   WHERE condition; 

2. SQL AVG() Function :
   The AVG() function provides the average value of a numeric column.

   AVG() Syntax –

   SELECT AVG(column_name)
   FROM table_name
   WHERE condition;
   

3. SQL SUM() Function :
   The SUM() function provides the total sum of a numeric column.

   SUM() Syntax –

   SELECT SUM(column_name)
   FROM table_name
   WHERE condition;
   

Let us assume, we have a table “GeeksTab”.

Name	City	Salary	ID	DOJ
Abc	Delhi	4500	134	6-Aug
Dfe	Noida	6500	245	4-March
Def	Jaipur	5400	546	2-July
Mno	Noida	7800	432	7-June
Jkl	Jaipur	5400	768	9-July
Lmn	Delhi	7800	987	8-June
Ijk	Jaipur	6700	654	5-June

1. COUNT() Example :
   The following SQL statement finds the number of Names in the “GeeksTab” table :

   SELECT COUNT(Name)
   FROM GeeksTab; 

   Output –

   7 

2. AVG() Example :
   The following SQL statement finds the average price of salary in the “GeeksTab” table :

   SELECT AVG(Salary)
   FROM GeeksTab; 

   Output –

   6300 

3. SUM() Example :
   The following SQL statement will find the sum of the Salary in the “GeeksTab” table :

   SELECT SUM(Salary)
   FROM GeeksTab; 

   Output –

   44100