/* Grouping the output */

SELECT   price, max(course_id), max(description)
FROM     course 
GROUP BY price;


SELECT   price, MAX(course_id), MAX(description)
FROM     course 
WHERE    description LIKE '%Web%'
GROUP BY price;


SELECT   price, MAX(course_id), description
FROM     course 
WHERE    description LIKE '%Web%'
GROUP BY price, description;


SELECT  vendor, SUM(amount) AS paid, COUNT(amount) AS tally, AVG(amount) average
FROM    payment 
GROUP BY vendor;


/* Multiple group by column */

SELECT  vendor, description, SUM(amount) paid, COUNT(amount) tally
FROM    payment 
GROUP BY vendor, description;


/* you can even group using functions */

SELECT  concat(vendor, description), sum(amount)  
FROM  payment 
WHERE description <> 'Home Insurance'
GROUP BY concat(vendor, description);