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SQL
Data Scientist
SQL questions
8 questions on SQL for data scientists, easiest first.
Easy
4
Counting orders per customer
easy
Customers with no orders
easy
Filtering groups in SQL
easy
COUNT of a column with NULLs
easy
Medium
3
Latest order per customer
medium
Ranking with ties in SQL
medium
NOT IN returns no rows
medium
Hard
1
LEFT JOIN that acts like INNER JOIN
hard
