April 2026
Beginner
493 pages
23h 2m
English
Content preview from SQL
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7.9 Summary
This chapter has been the most comprehensive part of the entire book. This is for good reason, too—DQL offers powerful tools for data extraction, and it’s arguably the most intensively used sublanguage of SQL.
After building the database of an imaginary online apparel store called Retro Loom, we learned about single table queries and multi table queries. We also covered table joins, subqueries, and set operations in depth.
We followed that with string, math, and temporal functions, which enable field calculations in data queries. We also covered powerful window functions that which empower us with the ability to conduct numeric calculations on intermediary results sets before building the final output.
Finally, we covered miscellaneous ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.