postgresql/no-not-in-subquery

Why this matters

`NOT IN` against a subquery returns **no rows** if the subquery yields a single NULL. Semantically correct under three-valued logic, virtually never what application code wants. Use `NOT EXISTS (...)` instead. `NOT IN (1, 2, 3)` with a literal list is unaffected.

Examples

SELECT id FROM users WHERE id NOT IN (SELECT user_id FROM blocks);

SELECT id FROM users u
WHERE NOT EXISTS (SELECT 1 FROM blocks b WHERE b.user_id = u.id);

SELECT 1 FROM users WHERE id NOT IN (1, 2, 3); -- literal list is fine

Configure it

// eslint.config.js
import postgresql from "eslint-plugin-postgresql";

export default [
  {
    files: ["**/*.sql"],
    languageOptions: {
      parser: postgresql.configs.recommended.languageOptions.parser,
    },
    plugins: { postgresql },
    rules: {
      "postgresql/no-not-in-subquery": "error",
    },
  },
];

Options

This rule has no options.