Merge pull request #618 from kicsiede/master

allow comparison with nullable parameter

Author: praeclarum

src/SQLite.cs

@@ -3574,8 +3574,13 @@ private string CompileNullBinaryExpression (BinaryExpression expression, Compile
 			if (expression.NodeType == ExpressionType.Equal)
 				return "(" + parameter.CommandText + " is ?)";
 			else if (expression.NodeType == ExpressionType.NotEqual)
-				return "(" + parameter.CommandText + " is not ?)";
-			else
+				return "(" + parameter.CommandText + " is not ?)";
+			else if (expression.NodeType == ExpressionType.GreaterThan
+				|| expression.NodeType == ExpressionType.GreaterThanOrEqual
+				|| expression.NodeType == ExpressionType.LessThan
+				|| expression.NodeType == ExpressionType.LessThanOrEqual)
+				return "(" + parameter.CommandText + " < ?)"; // always false
+			else
 				throw new NotSupportedException ("Cannot compile Null-BinaryExpression with type " + expression.NodeType.ToString ());
 		}