检查 SQL 查询的索引使用、结果集限制、循环查询、批量更新删除及 NULL 语义问题

Check for: - Predicates that cannot use an index (leading wildcard, function on the column, implicit cast) - Missing index for the WHERE, JOIN or ORDER BY columns used here - Unbounded result sets with no LIMIT and no pagination - Query shapes the caller will execute in a loop (N+1) - UPDATE or DELETE with a WHERE that can match every row - SQL assembled by string concatenation instead of parameters - NULL semantics: NOT IN against a nullable subquery, `= NULL`