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

dist/metona-sqlark.cjs.js

@@ -1614,6 +1614,11 @@ class QueryExecutor {
         return this.engine.createTable(createSchema(stmt.name, columns));
     }
     async executeDropTable(stmt) {
+        if (stmt.ifExists) {
+            const exists = await this.engine.hasTable(stmt.name);
+            if (!exists)
+                return; // IF EXISTS: 表不存在时静默返回
+        }
         return this.engine.dropTable(stmt.name);
     }
     getEngine() { return this.engine; }
@@ -1766,6 +1771,9 @@ var TokenType;
     TokenType["TRUE"] = "TRUE";
     TokenType["REFERENCES"] = "REFERENCES";
     TokenType["CASCADE"] = "CASCADE";
+    TokenType["BETWEEN"] = "BETWEEN";
+    TokenType["IF"] = "IF";
+    TokenType["EXISTS"] = "EXISTS";
     TokenType["FALSE"] = "FALSE";
     // JOIN 相关
     TokenType["INNER"] = "INNER";
@@ -1842,6 +1850,9 @@ const KEYWORDS = {
     'FALSE': TokenType.FALSE,
     'REFERENCES': TokenType.REFERENCES,
     'CASCADE': TokenType.CASCADE,
+    'BETWEEN': TokenType.BETWEEN,
+    'IF': TokenType.IF,
+    'EXISTS': TokenType.EXISTS,
     // JOIN
     'INNER': TokenType.INNER,
     'LEFT': TokenType.LEFT,
@@ -2451,8 +2462,15 @@ class Parser {
     parseDropTable() {
         this.expect(TokenType.DROP);
         this.expect(TokenType.TABLE);
+        // IF EXISTS（可选）
+        let ifExists = false;
+        if (this.curTokenIs(TokenType.IF)) {
+            this.nextToken();
+            this.expect(TokenType.EXISTS);
+            ifExists = true;
+        }
         const tableName = this.expectIdentifier('table name');
-        return { type: 'DROP_TABLE', name: tableName };
+        return { type: 'DROP_TABLE', name: tableName, ifExists: ifExists || undefined };
     }
     // ===================================================================
     //  条件表达式
@@ -2503,6 +2521,27 @@ class Parser {
             result[column] = isNot ? { $ne: null } : { $eq: null };
             return result;
         }
+        // BETWEEN val1 AND val2
+        if (this.curTokenIs(TokenType.BETWEEN)) {
+            this.nextToken();
+            const low = this.parseValue();
+            this.expect(TokenType.AND);
+            const high = this.parseValue();
+            const result = {};
+            result[column] = { $gte: low, $lte: high };
+            return result;
+        }
+        // NOT BETWEEN val1 AND val2
+        if (this.curTokenIs(TokenType.NOT) && this.peekTokenIs(TokenType.BETWEEN)) {
+            this.nextToken(); // skip NOT
+            this.nextToken(); // skip BETWEEN
+            const low = this.parseValue();
+            this.expect(TokenType.AND);
+            const high = this.parseValue();
+            const result = {};
+            result[column] = { $not: { $gte: low, $lte: high } };
+            return result;
+        }
         // NOT LIKE / NOT IN（NOT 后紧跟 LIKE 或 IN）
         if (this.curTokenIs(TokenType.NOT)) {
             if (this.peekTokenIs(TokenType.IN)) {