Real solutions to SQL → ActiveRecord translation problems. Learn why your queries break, how to fix them, and what Rails actually generates.
New to ActiveRecord? These posts explain the mental model differences that cause bugs.
LEFT JOINs that become INNER JOINs, multiple conditions, and association gotchas
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How to express INNER JOINs with multiple conditions in Rails without changing semantics by accident. Learn when Rails puts predicates in WHERE vs ON, how merge/default_scope can surprise you, and the patterns that stay correct when you later switch to LEFT JOIN.
LEFT JOIN queries often break the moment you add a WHERE on the joined table—silently turning into INNER JOIN behavior. Learn the correct Rails patterns (ON vs WHERE, scoped associations, where.missing/where.associated, EXISTS) and how to verify generated SQL.
Need a FULL OUTER JOIN in Rails? Learn why ActiveRecord doesn’t support it natively and the safest Postgres + UNION workarounds for production.
N+1 queries, includes() side effects, and when ActiveRecord makes things slower
A production-focused preview of Rails 8.2 explaining real-world impact on caching, TypeScript integration, Turbo behavior, and upgrade risks.
Copied SQL into Rails and still got N+1? Rewrote in ActiveRecord and still got N+1? The fix is a set-based mental model: where N+1 really comes from, how to verify it, and the AR patterns that eliminate it safely.
Ruby 4.0.0 is released (Dec 25, 2025). For Rails apps, the real risks are stdlib gem changes (CGI), Net::HTTP behavior shifts, and Bundler 4. Here’s what breaks first, how to fix safely, and what Ruby 4 performance does—and doesn’t—solve.
Need a FULL OUTER JOIN in Rails? Learn why ActiveRecord doesn’t support it natively and the safest Postgres + UNION workarounds for production.
Need an ActiveRecord cross join? Learn when SQL CROSS JOIN is justified, how to express it in Rails safely, and how to avoid row explosions in production.
LEFT JOIN queries often break the moment you add a WHERE on the joined table—silently turning into INNER JOIN behavior. Learn the correct Rails patterns (ON vs WHERE, scoped associations, where.missing/where.associated, EXISTS) and how to verify generated SQL.
How to do a SQL CROSS JOIN from ActiveRecord safely: when it’s the right tool, how to express it without losing bind params, and how to avoid accidental Cartesian products.
How to express INNER JOINs with multiple conditions in Rails without changing semantics by accident. Learn when Rails puts predicates in WHERE vs ON, how merge/default_scope can surprise you, and the patterns that stay correct when you later switch to LEFT JOIN.
Ruby 4.0.0 is released (Dec 25, 2025). For Rails apps, the real risks are stdlib gem changes (CGI), Net::HTTP behavior shifts, and Bundler 4. Here’s what breaks first, how to fix safely, and what Ruby 4 performance does—and doesn’t—solve.
Copied SQL into Rails and still got N+1? Rewrote in ActiveRecord and still got N+1? The fix is a set-based mental model: where N+1 really comes from, how to verify it, and the AR patterns that eliminate it safely.
If you know SQL, ActiveRecord can feel pointless—until it saves you from consistency bugs. Here’s the mental model: where SQL alone breaks app invariants, and how to use AR without losing performance.
A production-minded guide to building a modular monolith in Rails using Engines: where boundaries usually leak, how to structure code, and the upgrade-safe patterns that prevent cross-domain coupling.
A production-minded Rails 8.1 devcontainer setup that standardizes Ruby, Node, Postgres, and tooling across a team—plus the real failure modes and how to avoid them.
Ruby 3.5 was released as a preview; Ruby 4.0 shipped. Here’s what actually matters for Rails apps: what won’t change, what can break, and where SQL/ActiveRecord fixes beat runtime upgrades.
A production-focused preview of Rails 8.2 explaining real-world impact on caching, TypeScript integration, Turbo behavior, and upgrade risks.