How to use Arel? Wrong answers only!
summary
Shows using ActiveRecord and Arel visitor to traverse ASTs, collect table aliases, and rewrite them so merged scopes produce a single join instead of slow subqueries. Demonstrates why naive hash conditions cause alias mismatches and SQL injection risk, then builds a custom walker that maps aliases, swaps aliases across trees, and copies nodes to avoid cached mutation. Result: a working but fragile hack that fixes one query pattern at the cost of brittle, implementation-dependent code.
AI-written summary · about
