[Type A] Chapter – 14 Class 12 CS – Sumita Arora Assignment | Q/A

The SQL ORDER BY clause is used to sort the data in ascending or descending order, based on one or more columns. SQL sort the query results in ascending order by default.

SQL sort the query results in ascending order by default.

ASC is for the ascending order sorting and DESC is for the descending order sorting.
Such as in below shown code.

SELECT * FROM STUDENT1
ORDER BY AvgMark DESC;

SELECT prod_id, prod_price, prod_name, pros_discount FROM Products 
ORDER BY prod_price, prod_name, prod_discount DESC;

SELECT Project-Group, section, Marks FROM Student 
ORDER BY Project-Group ASC, section DESC, Marks DESC;

The main difference between WHERE and HAVING clause comes when used together with GROUP BY clause, in this case WHERE is used to filter rows before grouping and HAVING is used to exclude records after grouping.

GROUP BY clause can be used in a SELECT statement to collect data across multiple records and group the results by one or more columns with ease.

An aggregate function performs a calculation one or more values and returns a single value.
The aggregate function is often used with the GROUP BY clause and HAVING clause of the SELECT statement.

Some examples are SUM(), COUNT(), MIN(), MAX(), VAR(), STDEV().

The SELECT statement used in the GROUP BY clause can only be used contain column names, aggregate functions, constants and expressions.
The HAVING clause is used to restrict the results returned by the GROUP BY clause.