feat: SQL 语法支持 BETWEEN AND、DROP TABLE IF EXISTS

site/demo.html

@@ -422,7 +422,7 @@ FROM users u INNER JOIN orders o ON u.id = o.user_id
 GROUP BY u.name
 HAVING SUM(o.amount) > (SELECT AVG(amount) FROM orders);`,
   cascade: `-- 外键级联：重建 orders 表带 CASCADE
-DROP TABLE orders;
+DROP TABLE IF EXISTS orders;
 
 CREATE TABLE orders (
   id STRING PRIMARY KEY,
@@ -447,9 +447,9 @@ DELETE FROM users WHERE id = '1';
 -- 确认级联结果
 SELECT u.name, o.product, o.amount
 FROM users u LEFT JOIN orders o ON u.id = o.user_id;`,
-  adv: `-- 复杂条件：年龄 20-30 且不是 Bob
+  adv: `-- BETWEEN 范围查询
 SELECT * FROM users
-WHERE age >= 20 AND age <= 30 AND name != 'Bob'
+WHERE age BETWEEN 20 AND 30 AND name != 'Bob'
 ORDER BY age DESC;
 
 -- DISTINCT 去重