postgresql/prefer-coalesce-over-case

Why this matters

`COALESCE` is shorter, evaluates `x` once, and is the form every PostgreSQL planner optimizes directly. Also catches the mirrored `IS NOT NULL` form. Multi-arm CASEs that go beyond a single null-fallback are not flagged.

Examples

SELECT CASE WHEN nickname IS NULL THEN full_name ELSE nickname END FROM users;

SELECT CASE WHEN nickname IS NOT NULL THEN nickname ELSE full_name END FROM users;

SELECT COALESCE(nickname, full_name) FROM users;

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/prefer-coalesce-over-case": "warn",
    },
  },
];

Options

This rule has no options.