SQL Foundations: SELECT, Filters, Sorting & Aggregates
Read and reason through real SQL on a fictional bookshop database: SELECT, WHERE, AND/OR, IN, BETWEEN, LIKE, NULL, ORDER BY, LIMIT, aggregates, GROUP BY, HAVING and INSERT/UPDATE/DELETE, with every answer checked as you go.
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About this course
SQL Foundations teaches you to read and predict real SQL queries. You work with a small fictional bookshop database, a books table and an orders table, and in every lesson you work out exactly what a query returns: which rows a WHERE keeps, how AND, OR, IN, BETWEEN and LIKE behave, what NULL does to comparisons and averages, how ORDER BY, LIMIT and OFFSET build top lists and pages, and how COUNT, SUM, AVG, GROUP BY and HAVING turn rows into reports. You also see what INSERT, UPDATE and DELETE change, debug broken queries and finish with a complete report query. Every answer is checked instantly, and the first lesson is free.
Lessons
- SELECT: Choose Columns and Calculate New OnesFree
- WHERE: Keep Only the Rows You Need Locked
- AND, OR, NOT and Why Parentheses Matter Locked
- IN and BETWEEN: Lists and Ranges Locked
- LIKE Patterns: Searching Text with % and _ Locked
- ORDER BY: Sort Results Your Way Locked
- LIMIT, TOP and OFFSET: Top-N Lists and Pages Locked
- DISTINCT: Remove Duplicate Rows Locked
- NULL: Missing Values, IS NULL and IS NOT NULL Locked
- NULL in Calculations: COUNT(*) vs COUNT(column), COALESCE Locked
- Aggregate Functions: COUNT, SUM, AVG, MIN, MAX Locked
- Aggregates with WHERE: Filtered Totals Locked
- GROUP BY: One Result Row per Group Locked
- GROUP BY Several Columns: Groups That Exist Locked
- HAVING: Filter Groups After Aggregating Locked
- The Logical Order of a Query: FROM to LIMIT Locked
- INSERT: Adding Rows to a Table Locked
- UPDATE: Changing Rows (and Why WHERE Matters) Locked
- DELETE: Removing Rows Safely Locked
- Debug Lab: Spot and Fix Broken Queries Locked
- Final Project: The Monthly Genre Report Locked