Custom field filtering Why does this work fine

{% paginate craft.entries().limit(7).section('events').eventStartDate('&gt;= ' ~ 2014 ~ '-' ~ 09) as entriesOnPage %}


But this does not

{% paginate craft.entries().limit(7).section('events').eventStartDate('&gt;= ' ~ 2014 ~ '-' ~ 09) as entriesOnPage %}


I get this http://d.pr/i/NRvg

I also get errors when simply using '&lt;' so it seems to require only either a less than or equal to or a greater than or equal to operator.

Can someone point to some kind of documentation for what is allowed within the custom field filter -------------> this part ('&lt;= ' ~ 2014 ~ '-' ~ 09)
You shouldn't need to use string concatenation here:

.eventStartDate('&gt;= ' ~ 2014 ~ '-' ~ 09)


If you're hard coding the year and month, just use:

.eventStartDate('&gt;= 2014-09-01')