Data Engineer SQL Roadmap
Data engineers are the architects of the data stack. Focus heavily on DDL structures, structural constraints, high-scale aggregations, partition boundaries, CTE modeling, and upsert logic.
SQL SELECT & Projection
Master the entry point of data extraction: querying columns and renaming with AS.
WHERE Filters & Conditional Logic
Learn to surgically extract specific rows of data using conditional filtering.
SQL Aggregations & COUNT
Compile high-level math summaries like sums and averages over row matrices.
GROUP BY & HAVING Aggregations
Segment your summaries across specific categories and filter aggregated stats.
INNER JOIN Table Relations
Unlock the power of relational databases: link multiple tables together.
LEFT OUTER Joins
Preserve left-hand records and locate missing or orphaned data relationships.
Common Table Expressions (CTEs)
Write clean, highly readable, multi-stage pipelines using the WITH clause.
Advanced Window Functions
Compute moving averages, cumulative sums, and department rankings.
DDL: Tables & Data Types
Define relational physical table blueprints, data types, primary keys, and constraints.
Relational Integrity Constraints
Enforce primary keys, foreign keys, unique tags, check thresholds, and defaults.
The MERGE Statement (Upsert)
High-performance conditional insert, update, or delete in a single pass.
Set Operators (UNION vs UNION ALL)
Stack query results vertically and evaluate deduplication performance overhead.
Self Joins & Hierarchical Data
Join a table to itself to resolve recursive organizational trees or parent ledgers.