The foundation course is for beginners to SQL. It covers:
- the SELECT statement to retrieve data,
- column lists,
- the WHERE clause to filter data,
- the ORDER BY clause to sort data,
- creating calculated columns,
- the GROUP BY clause and aggregation functions such as COUNT() and SUM() to summarise data, and
- an introduction to joining tables to return a dataset that combines data from more than one table.
The intermediate course follows on from the foundation course. It covers:
- more detailed examples of joining tables e.g. LEFT and OUTER joins,
- sub-queries,
- common table expressions (CTEs),
- temporary tables,
- the CASE statement, and
- dealing with NULLs (missing values).
The advanced course follows on from the intermediate course. It covers:
- Window functions and their uses e.g., ratio calculations, cumulative totals, finding the top N items in each category and
- creating and using tally tables
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