Skip to content

CodingFoundations

SQL

Easy

Medium

Hard

Continue Read the guide View as list

StatusFormatCompany style

Easy

Every employee with their departmentSQLSQL8 min Headcount per departmentSQLSQL8 min Orders per statusSQLSQL7 min The highest and lowest salary on recordSQLSQL7 min Who has no salary recordedSQLSQL8 min Orders with the customer countrySQLSQL8 min How many of each eventSQLSQL7 min Monthly revenue from live subscriptionsSQLSQL8 min Posts with their authorSQLSQL8 min Authors with no country on fileSQLSQL8 min How many students per courseSQLSQL8 min

Medium

Departments with nobody in themSQLSQL10 min The average that a NULL salary ruinsSQLSQL10 min Customers who spent over a thresholdSQLSQL10 min Everyone and their managerSQLSQL12 min Salaries paid to more than one personSQLSQL10 min Paid more than their department averageSQLSQL12 min Revenue by monthSQLSQL10 min A salary column with no blanksSQLSQL9 min Hires per yearSQLSQL10 min Managers onlySQLSQL10 min Payroll by department, biggest firstSQLSQL10 min Customers who never orderedSQLSQL10 min

Hard

The second-highest salary in each departmentSQLSQL14 min A running total of revenue by dateSQLSQL14 min Each salary against the department bestSQLSQL12 min The most recent hire in each departmentSQLSQL13 min Paid and refunded side by sideSQLSQL13 min Each customer's previous order dateSQLSQL13 min Each customer's largest paid orderSQLSQL14 min Ordered within thirty days of signing upSQLSQL13 min Signed up, viewed, purchasedSQL · Meta styleMeta styleSQLMeta style14 min Users active on more than one daySQLSQL14 min The first event of every sessionSQLSQL15 min Did each user ever purchaseSQLSQL13 min