Update comparison.md

Author: zhangysh1995

comparison.md

@@ -5,26 +5,32 @@
 * integrity (testing)
 * mutation (testing)
 
-| Tool      | Scope              | Method       | Year | Pub*    | Author      |
-|:----------|:-------------------|:-------------|:-----|:--------|:------------|
-| N/A       | database           | parallel     | 94   | SIGMOD  | Bell Lab    |
-| N/A       | sql                | stochastic   | 98   | VLDB    | Microsoft   |
-| N/A       | sql                | ???          | 04   | SIGSOFT | Oviedo      |
-| N/A       | performance        | template     | 04   | VLDB    | Oracle      |
-| N/A       | database           | stochastic   | 05   | VLDB    | Microsoft   |
-| N/A       | sql/coverage       | genetic      | 07   | VLDB    | Microsoft   |
-| RQP       | functionality      | constraints  | 07   | ICDE    | ETH Zurich  |
-| QAGen     | database           | constraints  | 07   | SIGMOD  | ETH Zurich  |
-| ADUSA     | verification       | constraints  | 08   | ASE     | UT Austin   |
-| Qex       | database           | constraints  | 09   | LPAR    | Microsoft   |
-| N/A       | sql/execution      | differential | 09   | SIGMOD  | Microsoft   |
-| ??        | verification       | ??           | 10   | POPL    | Harvard     |
-| N/A       | predicate/mutation | constraints  | 10   | STVR    | Oviedo      |
-| CorrectDB | authentication     | ??           | 13   | VLDB    | Stony Brook |
-| N/A       | database/mutation  | constraints  | 15   | VLDB    | IIT         |
-| N/A       | integrity          | mutation     | 15   | TOSEM   | Sheffield   |
-| EvoSQL    | sql                | search       | 18   | ICSE    | Delft       |
-| Apollo    | performance        | differential | 19   | VLDB    | Geogia Tech |
+| Tool      | Scope              | Method       | Year | Pub*   | Author      |
+|:----------|:-------------------|:-------------|:-----|:-------|:------------|
+| N/A       | database           | parallel     | 94   | SIGMOD | Bell Lab    |
+| N/A       | sql                | stochastic   | 98   | VLDB   | Microsoft   |
+| N/A       | performance        | template     | 04   | VLDB   | Oracle      |
+| N/A       | database           | stochastic   | 05   | VLDB   | Microsoft   |
+| N/A       | sql/coverage       | genetic      | 07   | VLDB   | Microsoft   |
+| RQP       | functionality      | constraints  | 07   | ICDE   | ETH Zurich  |
+| QAGen     | database           | constraints  | 07   | SIGMOD | ETH Zurich  |
+| ADUSA     | verification       | constraints  | 08   | ASE    | UT Austin   |
+| Qex       | database           | constraints  | 09   | LPAR   | Microsoft   |
+| N/A       | sql/execution      | differential | 09   | SIGMOD | Microsoft   |
+| ??        | verification       | ??           | 10   | POPL   | Harvard     |
+| N/A       | predicate/mutation | constraints  | 10   | STVR   | Oviedo      |
+| CorrectDB | authentication     | ??           | 13   | VLDB   | Stony Brook |
+| N/A       | database/mutation  | constraints  | 15   | VLDB   | IIT         |
+| N/A       | integrity          | mutation     | 15   | TOSEM  | Sheffield   |
+| EvoSQL    | sql                | search       | 18   | ICSE   | Delft       |
+| Apollo    | performance        | differential | 19   | VLDB   | Geogia Tech |
+
+
+Unclassified (no suitable catrgory):
+| Tool | Scope        | Method | Year | Pub*    | Author |
+|:-----|:-------------|:-------|:-----|:--------|:-------|
+| N/A  | sql/coverage | ???    | 04   | SIGSOFT | Oviedo |
+
 
 
 Necessary background to understand the research: