[Minor] Add cases from Issue

src/optimizer/OptimizerUtils.cpp

@@ -813,7 +813,7 @@ bool OptimizerUtils::findOptimalIndex(const Expression* condition,
                                       const std::vector<std::shared_ptr<IndexItem>>& indexItems,
                                       bool* isPrefixScan,
                                       IndexQueryContext* ictx) {
-    // Return directly if there is not valid index to use.
+    // Return directly if there is no valid index to use.
     if (indexItems.empty()) {
         return false;
     }

tests/tck/features/bugfix/StringFlaotAddition.feature

@@ -0,0 +1,69 @@
+# Copyright (c) 2021 vesoft inc. All rights reserved.
+#
+# This source code is licensed under Apache 2.0 License,
+# attached with Common Clause Condition 1.0, found in the LICENSES directory.
+Feature: Test return float plus string
+
+  Background:
+    Given a graph with space named "nba"
+
+  # Fix https://github.com/vesoft-inc/nebula-graph/issues/1214
+  Scenario: addition[1]
+    When executing query:
+      """
+      RETURN 30.142857142857142 + "Yao Ming"
+      """
+    Then the result should be, in any order, with relax comparison:
+      | (30.142857142857142+"Yao Ming") |
+      | "30.142857142857142Yao Ming"    |
+    When executing query:
+      """
+      RETURN -30.142857142857142 + "Yao Ming"
+      """
+    Then the result should be, in any order, with relax comparison:
+      | (-(30.142857142857142)+"Yao Ming") |
+      | "-30.142857142857142Yao Ming"      |
+    When executing query:
+      """
+      RETURN "Yao Ming" + 30.142857142857142
+      """
+    Then the result should be, in any order, with relax comparison:
+      | ("Yao Ming"+30.142857142857142) |
+      | "Yao Ming30.142857142857142"    |
+    When executing query:
+      """
+      RETURN "Yao Ming" + -30.142857142857142
+      """
+    Then the result should be, in any order, with relax comparison:
+      | ("Yao Ming"+-(30.142857142857142)) |
+      | "Yao Ming-30.142857142857142"      |
+
+  Scenario: addition[2]
+    When executing query:
+      """
+      RETURN 30.14 + "Yao Ming"
+      """
+    Then the result should be, in any order, with relax comparison:
+      | (30.14+"Yao Ming") |
+      | "30.14Yao Ming"    |
+    When executing query:
+      """
+      RETURN -30.14 + "Yao Ming"
+      """
+    Then the result should be, in any order, with relax comparison:
+      | (-(30.14)+"Yao Ming") |
+      | "-30.14Yao Ming"      |
+    When executing query:
+      """
+      RETURN "Yao Ming" + 30.14
+      """
+    Then the result should be, in any order, with relax comparison:
+      | ("Yao Ming"+30.14) |
+      | "Yao Ming30.14"    |
+    When executing query:
+      """
+      RETURN "Yao Ming" + -30.14
+      """
+    Then the result should be, in any order, with relax comparison:
+      | ("Yao Ming"+-(30.14)) |
+      | "Yao Ming-30.14"      |