diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index 6762d68cc..fbadd7c0c 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -1852,6 +1852,7 @@ Zotero.Date = new function(){
 	// TODO: Allow negative multipart in DB and here with \-?
 	var _multipartRE = /^[0-9]{4}\-(0[0-9]|10|11|12)\-(0[0-9]|[1-2][0-9]|30|31) /;
 	var _sqldateRE = /^\-?[0-9]{4}\-(0[1-9]|10|11|12)\-(0[1-9]|[1-2][0-9]|30|31)$/;
+	var _sqldateWithZeroesRE = /^\-?[0-9]{4}\-(0[0-9]|10|11|12)\-(0[0-9]|[1-2][0-9]|30|31)$/;
 	var _sqldatetimeRE = /^\-?[0-9]{4}\-(0[1-9]|10|11|12)\-(0[1-9]|[1-2][0-9]|30|31) ([0-1][0-9]|[2][0-3]):([0-5][0-9]):([0-5][0-9])$/;
 	
 	/**
@@ -1900,7 +1901,10 @@ Zotero.Date = new function(){
 	}
 	
 	
-	function isSQLDate(str){
+	function isSQLDate(str, allowZeroes) {
+		if (allowZeroes) {
+			return _sqldateWithZeroesRE.test(str);
+		}
 		return _sqldateRE.test(str);
 	}
 	
@@ -1911,17 +1915,17 @@ Zotero.Date = new function(){
 	
 	
 	function sqlHasYear(sqldate){
-		return isSQLDate(sqldate) && sqldate.substr(0,4)!='0000';
+		return isSQLDate(sqldate, true) && sqldate.substr(0,4)!='0000';
 	}
 	
 	
 	function sqlHasMonth(sqldate){
-		return isSQLDate(sqldate) && sqldate.substr(5,2)!='00';
+		return isSQLDate(sqldate, true) && sqldate.substr(5,2)!='00';
 	}
 	
 	
 	function sqlHasDay(sqldate){
-		return isSQLDate(sqldate) && sqldate.substr(8,2)!='00';
+		return isSQLDate(sqldate, true) && sqldate.substr(8,2)!='00';
 	}