SQL

Question 1

SELECT aisle, SUM(quantity) FROM groceries GROUP BY aisle;

Answer 1

SELECT aisle, SUM(quantity) FROM groceries GROUP BY aisle;

• remember if you ‘SELECT name’ it won’t give you meaningful results. ‘SELECT x’ should be the same as the ‘GROUP BY x’

Question 2

Give an example of sub query

Answer 2

SELECT * FROM exercise_logs WHERE type IN (
SELECT type FROM drs_favorites);

the query in the () is the inner query. What this does is it selects the results that appear in the drs_favorites table that also appears in the exercise logs table (which is a larger table)

// eg using LIKE

SELECT * FROM exercise_logs WHERE type IN (
SELECT type FROM drs_favorites WHERE reason LIKE “%cardiovascular%”);

(as seen in More advanced SQL queries video 3). NB the % above act as a wildcard