Handle empty result sets

conn.go

@@ -663,8 +663,12 @@ func (cn *conn) simpleQuery(q string) (res *rows, err error) {
 			// Set the result and tag to the last command complete if there wasn't a
 			// query already run. Although queries usually return from here and cede
 			// control to Next, a query with zero results does not.
-			if t == 'C' && res.colNames == nil {
+			if t == 'C' {
 				res.result, res.tag = cn.parseComplete(r.string())
+				if res.colNames != nil {
+					res.tag = ""
+					return
+				}
 			}
 			res.done = true
 		case 'Z':

conn_test.go

@@ -1748,6 +1748,36 @@ func TestMultipleResult(t *testing.T) {
 	}
 }
 
+func TestMultipleEmptyResult(t *testing.T) {
+	db := openTestConn(t)
+	defer db.Close()
+
+	rows, err := db.Query("select 1 where false; select 2")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rows.Close()
+
+	for rows.Next() {
+		t.Fatal("unexpected row")
+	}
+	if !rows.NextResultSet() {
+		t.Fatal("expected more result sets", rows.Err())
+	}
+	for rows.Next() {
+		var i int
+		if err := rows.Scan(&i); err != nil {
+			t.Fatal(err)
+		}
+		if i != 2 {
+			t.Fatalf("expected 2, got %d", i)
+		}
+	}
+	if rows.NextResultSet() {
+		t.Fatal("unexpected result set")
+	}
+}
+
 func TestCopyInStmtAffectedRows(t *testing.T) {
 	db := openTestConn(t)
 	defer db.Close()