SQL Essentials: The Beginner's Guide to SQL Language

Work through exercise 3 solutions, selecting from band where name equals 'Icarus', then use year IS NULL with AND; avoid year = NULL, which returns no rows.

Explore data aggregation with count, group by, and where to compute row counts and group results by band_id and year using the album table.

Explore left outer joins to retain rows with no matches, using NULLs for missing band data, and see how where vs on clause affects results.

Explore solving sql exercises by counting Led Zeppelin albums per year using a calendar_year lookup. Apply left outer joins, group by year, and count(album_id) to show zero years.

Explore self joins to relate rows within the same table, using a music instrument hierarchy to show parent, grandparent, and child relationships with left outer joins.

Learn to query a music instruments hierarchy in a single table using self-joins across levels, left joins, and counts of non-null ids to identify the bottom of the hierarchy.

Explore cross joins, or cartesian joins, which pair every row from the first table with every row from the second when no join condition is specified.

Learn how except all (also called minus) subtracts rows from one query and how duplicates are retained or removed. Explore null values, not in, and coalesce effects on results.

Explore the intersect and intersect all operators to find common rows across queries, handle duplicates, and manage null values with cautious subqueries and coalesce considerations.

Overview of functions and operators in SQL, including logical and comparison operators, the like operator, mathematical operators, and concatenation ||; learn the most frequently used SQL functions.

Use update to modify existing rows, not add new ones, with syntax: update table set column = value where condition; you can also update from another table via a join.