Data Science SkillsCompany: LinkedIn | Difficulty: easy

Given a table of candidates and their skills, you're tasked with finding the candidates best suited for an open Data Science job. You want to find candidates who are proficient in Python, Tableau, and PostgreSQL.

Write a query to list the candidates who possess all of the required skills for the job. Sort the output by candidate_id in descending order.

Table Schema

Table	Column	Type
`candidates`	`candidate_id`	integer
`candidates`	`skill`	string

Example Input: `candidates`

candidate_id	skill
123	Python
123	Tableau
123	PostgreSQL
234	R
234	PowerBI
345	Python
345	Tableau

Example Output Explanation

Candidate 123 has Python, Tableau, and PostgreSQL. Candidate 234 lacks Python and PostgreSQL. Candidate 345 has Python and Tableau, but is missing PostgreSQL. Therefore, only candidate 123 is returned.

SchemaDROP TABLE IF EXISTS candidates; CREATE TABLE candidates (candidate_id INT, skill VARCHAR(50)); INSERT INTO candidates VALUES (123, 'Python'), (123, 'Tableau'), (123, 'PostgreSQL'), (234, 'R'), (234, 'PowerBI'), (234, 'SQL Server'), (345, 'Python'), (345, 'Tableau');← All SQL Challenges · LinkedIn Questions · Learn SQL Free