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Lessons/Data Science and Decision Intelligence/Beginner/SQL for Data Professionals

SELECT, WHERE, and Aggregations

35 min Coding Lab
Write SELECT queries with WHERE filtersUse GROUP BY with aggregate functionsSort results with ORDER BY

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35 min
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SQL: The Language of Data

SQL is the universal language for querying relational databases. As a data professional, you will use SQL daily — to extract data for analysis, build dashboards, validate pipelines, and feed models.

Core Query Structure

Every SQL query follows the same logical order: SELECT columns, FROM table, WHERE conditions, GROUP BY categories, HAVING group filters, ORDER BY sorting. Mastering this structure lets you answer any data question.

Key Takeaway

SQL is non-negotiable for data professionals. Master SELECT, WHERE, GROUP BY, and JOIN — they cover 90% of real-world queries.

Review Questions

1. What does GROUP BY do in a SQL query?