DATACAMP- Intro to SQL and Joins with PostgreSQL| EXAM PRACTICE QUESTIONS AND CORRECT ANSWERS (100% CORRECT VERIFIED ANSWERS) 2024/2025

DATACAMP- Intro to SQL and Joins with
PostgreSQL| EXAM PRACTICE QUESTIONS AND
CORRECT ANSWERS (100% CORRECT VERIFIED
ANSWERS) 2024/2025

AVG - ✔✔calculate the mean of specific column values (ignoring NULL values)



MAX - ✔✔calculate the maximum of specific column values



SUM - ✔✔add all the values in a specific column together



MIN - ✔✔calculate the minimum of specific column values



ORDER BY - ✔✔sort the query results



DESC - ✔✔specify that sorting should be done from largest number to smallest



GROUP BY - ✔✔specify that calculations (like AVG, MIN, MAX) should be summarized
by another column's values



HAVING - ✔✔filter the results of a GROUP BY operation



JOIN - ✔✔connect two tables

, ON - ✔✔specify the primary key - foreign key pair on which to base the JOIN
operation



INNER JOIN - ✔✔a connection between two tables;includes only those rows with
matching primary key - foreign key values


USING - ✔✔like the ON keyword in a JOIN statement; used when primary key /
foreign key columns have the same name


CASE - ✔✔used within a query to identify complex conditions (similar to IF, ELSIF,
ELSE logic).



WHEN - ✔✔used within a CASE expression to identify conditions



THEN - ✔✔used within a CASE expression to identify returned results



ELSE - ✔✔used within a CASE expression to identify the result if all WHEN conditions
fail



END - ✔✔used to end a CASE expression



INTO - ✔✔used to store the results of a SELECT statement within a new table



LEFT JOIN - ✔✔returns all records from the left table (table1), and the matched
records from the right table (table2)