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Joins & Filtering - SQL Practical Query Problems | Aporeon

SQL Practical Query Problems

Joins & Filtering

Parent-child queries, anti-joins, many-to-many filters, range overlap, and duplicate-safe result shapes.

5 drillsPractice one at a timeOrdered pathCoding problem

Recommended start

Paid Order Totals

Writes a left-join aggregate that keeps active customers with no paid orders and applies date filters without changing join semantics.

Easy~15 minStep 1 of 5

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1Paid Order TotalsRecommended startWrites a left-join aggregate that keeps active customers with no paid orders and applies date filters without changing join semantics.Coding problemEasy~15 minSQLSQL ServerPractice 2

Practice order

5 drillsOne at a time

1Paid Order TotalsUp next / Easy / ~15 min
2Users Without OrdersEasy / ~15 min
3Match Every TagMedium / ~25 min
4

Users Without Orders

Uses NOT EXISTS to express an anti-join without null traps or duplicate parent rows.

Coding problemEasy~15 minSQLSQL Server

Practice

3Match Every TagSolves a many-to-many all-match filter with grouping and a deliberate empty-selection rule.Coding problemMedium~25 minSQLSQL ServerPractice

4Booking OverlapImplements correct half-open interval overlap logic for booking validation.Coding problemMedium~25 minSQLSQL ServerPractice

5Filter Without DuplicatesUses EXISTS instead of a row-multiplying join when the related table is only a filter.Coding problemEasy~15 minSQLSQL ServerPractice

Booking Overlap

Medium / ~25 min

5Filter Without DuplicatesEasy / ~15 min