Check out example codes for "group by sql". It will help you in understanding the concepts better.
Code Example 1
# Use SQL Group By clause after the Where clause
# Any column in the select list must either be in the Group By clause
# or part of an agregation statement
# Multiple columns can be included in the Group By Clause seperated by a comma
# Multiple columns stipulate the order tree. Order by
# first column, then second ... etc
Select LastName, FirstName, Sum(LeaveDays), Max(age)
From EmployeeProjects
Where StartDate > '2020-01-01'
Group By LastName, FirstName
Code Example 2
SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
HAVING condition
ORDER BY column_name(s);
Code Example 3
SELECT `gender` FROM `members` GROUP BY `gender`;
Code Example 4
SELECT <field1, field2, field3…>
FROM <table1_name>
WHERE <condition/expression>
GROUP BY <field1, field2, field3…>
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