/courses/sql/subqueries-ctes-and-views/Recent content in Subqueries, CTEs, and Views on DATATWEETSHugoenCopyright (c) 2025 DatatweetsTue, 23 Jun 2026 09:00:00 +0200/courses/sql/subqueries-ctes-and-views/lesson-1-scalar-subqueries/Fri, 14 Nov 2025 09:00:00 +0200/courses/sql/subqueries-ctes-and-views/lesson-1-scalar-subqueries/Learn what a subquery is, write scalar subqueries that return one value, and use them in SELECT, WHERE, and HAVING clauses to compare rows against computed benchmarks./courses/sql/subqueries-ctes-and-views/lesson-2-multi-row-and-multi-column-subqueries/Fri, 14 Nov 2025 09:00:00 +0200/courses/sql/subqueries-ctes-and-views/lesson-2-multi-row-and-multi-column-subqueries/Move beyond single values: write multi-row subqueries for IN and NOT IN filters, and multi-column subqueries that act as tables in the FROM clause and in joins./courses/sql/subqueries-ctes-and-views/lesson-3-nested-and-correlated-subqueries/Fri, 14 Nov 2025 09:00:00 +0200/courses/sql/subqueries-ctes-and-views/lesson-3-nested-and-correlated-subqueries/Write correlated subqueries that reference the outer query row by row, use EXISTS and NOT EXISTS, nest subqueries several levels deep, and approach complex problems systematically./courses/sql/subqueries-ctes-and-views/lesson-4-common-table-expressions-ctes/Fri, 14 Nov 2025 09:00:00 +0200/courses/sql/subqueries-ctes-and-views/lesson-4-common-table-expressions-ctes/Name your subqueries with the WITH clause to write readable, reusable queries, chain multiple CTEs together, and traverse tree-structured tables with recursive CTEs./courses/sql/subqueries-ctes-and-views/lesson-5-creating-and-using-views/Fri, 14 Nov 2025 09:00:00 +0200/courses/sql/subqueries-ctes-and-views/lesson-5-creating-and-using-views/Turn a saved SELECT into a virtual table with CREATE VIEW, query views like tables, layer views on top of views, and remove them with DROP VIEW and CASCADE./courses/sql/subqueries-ctes-and-views/lesson-6-guided-project-customer-and-product-analysis/Fri, 14 Nov 2025 09:00:00 +0200/courses/sql/subqueries-ctes-and-views/lesson-6-guided-project-customer-and-product-analysis/Apply subqueries, CTEs, and views to a scale-model-car sales database: decide what to restock, rank your most valuable customers, and estimate how much to spend acquiring new ones.