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Over the years, I have come across multiple resources I learned things from with ease. This is a page to track those resources. Please reach out to me if you think something belongs to this list. I will add it. General Julia Evans has online zines for topics ranging from SQL, Shell scripts to Linux. These are hand-drawn explanations of stuff related to a particular topic. I stumbled upon here twitter post about how SQL actually executes a query and have been a fan ever since. ...

Comparison operators LIKE is case sensitive ILIKE is not BETWEEN includes the range bounds IS NULL is for missing values. column=NULL will not work. For non null values - use IS NOT NULL. Don’t use NOT IS NULL Aggregate function COUNT COUNT(col) gives of count of col where values are not null. This is the main difference between COUNT(*) and COUNT(col) SUM, AVG and COUNT can only be used for numeric values. (duh!) AVG ignores null values completely. Does not take in the denominator MIN and MAX can be used for numeric, date, chars GROUP BY ...