Can not parse concatenated columns #30

Hi,
Sql that involves concatenating a string to a column or two columns together can not be parsed.

e.g.
var sql = "select FIELD1 || FIELD2 from MYTABLE";
require('sql-parser').lexer.tokenize(sql);

results in:

Error: NOTHING CONSUMED: Stopped at - '|| FIELD2 from MYTABLE'
at new Lexer (C:\MyProject\node_modules\sql-parser\lib\lexer.js:21:17)

I use Firebird SQL, so I'm not sure if this is valid in other SQL dialects.