GROUPING

Question 1

GROUP BY

Answer 1

used to arrange identical data into groups. It’s often used with aggregate functions (COUNT, MAX, MIN, SUM, AVG) to group the result-set by one or more columns

Question 2

HAVING

Answer 2

works like the WHERE, but operates on grouped data, returned by the GROUP BY clause.

Question 3

UNION

Answer 3

combines the result of two or more SELECT queries into a single result set.

automatically eliminates duplicate row

must be compatible data type

Question 4

INTERSECT

Answer 4

returns the common records between two or more SELECT statements.