MetonaSqlark/tests/groupby.test.ts

/**
 * GROUP BY + 聚合函数测试 (v0.1.2)
 */

import { MetonaSqlark } from '../src/core';
import { parse } from '../src/sql/parser';
import type { SelectStatement } from '../src/query/ast';

/** v0.8.0: parse() 返回联合类型 Statement，需显式收窄后才能访问 SELECT 字段 */
function asSelect(stmt: ReturnType<typeof parse>): SelectStatement {
  expect(stmt.type).toBe('SELECT');
  if (stmt.type !== 'SELECT') throw new Error(`expected SELECT, got ${stmt.type}`);
  return stmt;
}

describe('GROUP BY (v0.1.2)', () => {
  let db: MetonaSqlark;

  beforeEach(async () => {
    db = new MetonaSqlark({ name: 'test-groupby', mode: 'memory' });
    await db.init();

    await db.defineTable('employees', {
      id: { type: 'string', primaryKey: true },
      name: { type: 'string', required: true },
      dept: { type: 'string' },
      salary: { type: 'number' },
    });

    await db.table('employees').insertMany([
      { id: '1', name: 'Alice', dept: 'Eng', salary: 1000 },
      { id: '2', name: 'Bob', dept: 'Eng', salary: 1200 },
      { id: '3', name: 'Charlie', dept: 'Sales', salary: 900 },
      { id: '4', name: 'Diana', dept: 'Sales', salary: 1100 },
      { id: '5', name: 'Eve', dept: 'HR', salary: 800 },
    ]);
  });

  afterEach(async () => {
    await db.close();
  });

  // ===================================================================
  //  SQL GROUP BY
  // ===================================================================

  describe('SQL GROUP BY', () => {
    it('GROUP BY + COUNT', async () => {
      const result = await db.query(
        'SELECT dept, COUNT(*) FROM employees GROUP BY dept',
      ) as Record<string, unknown>[];
      expect(result).toHaveLength(3);
      const eng = result.find((r: any) => r.dept === 'Eng');
      expect(eng!['COUNT(*)']).toBe(2);
    });

    it('GROUP BY + SUM', async () => {
      const result = await db.query(
        'SELECT dept, SUM(salary) FROM employees GROUP BY dept',
      ) as Record<string, unknown>[];
      const eng = result.find((r: any) => r.dept === 'Eng');
      expect(eng!['SUM(salary)']).toBe(2200);
    });

    it('GROUP BY + AVG', async () => {
      const result = await db.query(
        'SELECT dept, AVG(salary) FROM employees GROUP BY dept',
      ) as Record<string, unknown>[];
      const eng = result.find((r: any) => r.dept === 'Eng');
      expect(eng!['AVG(salary)']).toBe(1100);
    });

    it('GROUP BY + MIN/MAX', async () => {
      const result = await db.query(
        'SELECT dept, MIN(salary), MAX(salary) FROM employees GROUP BY dept',
      ) as Record<string, unknown>[];
      const eng = result.find((r: any) => r.dept === 'Eng');
      expect(eng!['MIN(salary)']).toBe(1000);
      expect(eng!['MAX(salary)']).toBe(1200);
    });

    it('GROUP BY + HAVING', async () => {
      const result = await db.query(
        'SELECT dept, COUNT(*) FROM employees GROUP BY dept HAVING COUNT(*) > 1',
      ) as Record<string, unknown>[];
      expect(result).toHaveLength(2); // Eng(2) + Sales(2)
    });

    it('GROUP BY + WHERE + HAVING', async () => {
      const result = await db.query(
        "SELECT dept, SUM(salary) FROM employees WHERE dept != 'HR' GROUP BY dept HAVING SUM(salary) > 2000",
      ) as Record<string, unknown>[];
      expect(result).toHaveLength(1); // Only Eng
    });

    it('聚合函数别名', async () => {
      const result = await db.query(
        'SELECT dept, COUNT(*) AS cnt, SUM(salary) AS total FROM employees GROUP BY dept',
      ) as Record<string, unknown>[];
      const eng = result.find((r: any) => r.dept === 'Eng');
      expect(eng!.cnt).toBe(2);
      expect(eng!.total).toBe(2200);
    });
  });

  // ===================================================================
  //  Parser 测试
  // ===================================================================

  describe('Parser', () => {
    it('解析 COUNT(*)', () => {
      const ast = asSelect(parse('SELECT COUNT(*) FROM employees'));
      expect(ast.columns[0]).toBe('COUNT(*)');
    });

    it('解析 GROUP BY', () => {
      const ast = asSelect(parse('SELECT dept, COUNT(*) FROM employees GROUP BY dept'));
      expect(ast.groupBy).toEqual(['dept']);
    });

    it('解析 HAVING', () => {
      const ast = asSelect(parse('SELECT dept, COUNT(*) FROM employees GROUP BY dept HAVING COUNT(*) > 1'));
      // v0.8.0: 断言真实结构而非 toBeDefined()
      expect(ast.having).toEqual({ 'COUNT(*)': { $gt: 1 } });
    });
  });
});