diff --git a/README.md b/README.md
@@ -10,6 +10,7 @@ sql grammar follows https://dev.mysql.com/doc/refman/5.7/en/select.html

## news

- Fix bug `using ' & " for column alias?` since v1.4.1 [#40](https://github.com/JavaScriptor/js-sql-parser/issues/40), [#44](https://github.com/JavaScriptor/js-sql-parser/issues/44)
- Fix bug tableFactor alias since v1.3.0 [#34](https://github.com/JavaScriptor/js-sql-parser/issues/34)
- Add support for "`" quoted alias since v1.2.2. [#33](https://github.com/JavaScriptor/js-sql-parser/issues/33)
@@ -35,6 +36,18 @@ console.log(parser.stringify(ast));
// SELECT foo FROM bar
```

## script tag

```js
@@ -60,10 +73,6 @@ var sql = sqlParser.stringify(ast);
- intervalexpr: Date INTERVAL keyword.   // to support
- into outfile: INTO OUTFILE keyword.    // to support

-## TODO
-
-- ${value} like value place holder support.
-
## Build

- Run `npm run build` to build the distributable.

diff --git a/src/sqlParser.jison b/src/sqlParser.jison
@@ -11,7 +11,7 @@
[#]\s.*\n                                                         /* skip sql comments */
\s+                                                               /* skip whitespace */

-[$][{](.*?)[}]                                                    return 'PLACE_HOLDER'
[`][a-zA-Z_\u4e00-\u9fa5][a-zA-Z0-9_\u4e00-\u9fa5]*[`]            return 'IDENTIFIER'
[\w]+[\u4e00-\u9fa5]+[0-9a-zA-Z_\u4e00-\u9fa5]*                   return 'IDENTIFIER'
[\u4e00-\u9fa5][0-9a-zA-Z_\u4e00-\u9fa5]*                         return 'IDENTIFIER'

diff --git a/src/stringify.js b/src/stringify.js
@@ -552,18 +552,6 @@ Sql.prototype.travelSelectParenthesized = function(ast) {
  this.appendKeyword(')');
};
Sql.prototype.travelPlaceHolder = function (ast) {
-  if (ast.left) {
-    this.travel(ast.left);
-  }
-
-  if (ast.operator) {
-    this.append(ast.operator);
-  }
-
-  if (ast.right) {
-    this.append(ast.right);
-  }
-
  if (ast.value) {
    this.travel(ast.value);
  }