SQL Joins, Indexes, and Query Plans for Beginners

Many developers use databases every day without learning how the database reads their queries. This workshop builds SQL confidence through small examples that connect query syntax to real performance behavior.

What we will cover

• Reading tables as sets of rows instead of spreadsheets
• Inner joins, left joins, grouping, and filtering without confusion
• The difference between primary keys, foreign keys, and indexes
• Why indexes help some queries and do nothing for others
• Reading a simple query plan to spot table scans
• Practical habits for naming, formatting, and testing queries

Who should attend

New backend developers, analysts, data science beginners, and anyone who has copied SQL but wants to understand it.

Takeaway

Attendees leave with a small query practice set, a clearer model for joins, and enough query-plan literacy to start debugging slow database work.