9 Extracting Information by Grouping and Summarizing
Every dataset tells a story, and it’s the data analyst’s job to find it. In Chapter 3, you learned about interviewing data using SELECT statements by sorting columns, finding distinct values, and filtering results. You’ve also learned the fundamentals of SQL math, data types, table design, and joining tables. With these tools under your belt, you’re ready to glean more insights by using grouping and aggregate functions to summarize your data.
By summarizing data, we can identify useful information we wouldn’t see just by scanning the rows of a table. In this chapter, we’ll use the well-known ...
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