Advanced SQL
Interview Patterns SQL Lessons
Learn duplicates, gaps & islands, anti-joins through focused tutorials and business-data examples.
Lessons in this category
SQL Find Duplicate RowsRead lesson SQL Remove Duplicate RowsRead lesson SQL Second Highest ValueRead lesson SQL Nth Highest ValueRead lesson SQL Latest Row per CustomerRead lesson SQL First Row per GroupRead lesson SQL Customers with No OrdersRead lesson SQL Missing Records Between TablesRead lesson SQL Anti-Join PatternRead lesson SQL Semi-Join PatternRead lesson SQL Consecutive DatesRead lesson SQL Gaps and IslandsRead lesson SQL Compare Consecutive RowsRead lesson SQL MedianRead lesson SQL PercentilesRead lesson SQL Pivot DataRead lesson SQL Unpivot DataRead lesson SQL Recursive HierarchyRead lesson