sql-review

# SQL Review - **Injection** — parameterized, always. No string interpolation into SQL. - **N+1** — a query inside a loop? Replace with a join or a batched IN. - **Missing index** — does the WHERE/JOIN/ORDER BY hit an indexed column? If not, the table scan will surface at scale. - **Unbounded** — SELECT with no LIMIT on a growing table; a JOIN that fans out rows. - **Transactions** — multi-write operations wrapped so a partial failure can't corrupt state. - **Migrations** — reversible (up AND down), and safe on a live table (no blocking lock on a hot table at peak). Output: each issue with the line and the rewrite. Show the EXPLAIN if performance is the concern.