improve sql wall

src/main/java/com/alibaba/druid/sql/dialect/mysql/parser/MySqlLexer.java

@@ -384,8 +384,15 @@ public class MySqlLexer extends Lexer {
 
     public void scanComment() {
         Token lastToken = this.token;
-
-        if (ch != '/' && ch != '-') {
+        
+        if (ch == '-') {
+            char next_2 = charAt(pos + 2);
+            if (isDigit(next_2)) {
+                scanChar();
+                token = Token.SUB;
+                return;
+            }
+        } else if (ch != '/') {
             throw new IllegalStateException();
         }
 

src/main/java/com/alibaba/druid/sql/parser/Lexer.java

@@ -173,7 +173,7 @@ public class Lexer {
     protected final void scanChar() {
         ch = charAt(++pos);
     }
-
+    
     protected void unscan() {
         ch = charAt(--pos);
     }

src/test/java/com/alibaba/druid/bvt/filter/wall/MySqlWallTest71.java

@@ -36,7 +36,7 @@ public class MySqlWallTest71 extends TestCase {
 
         provider.getConfig().setCommentAllow(true);
 
-        Assert.assertFalse(provider.checkValid(//
+        Assert.assertTrue(provider.checkValid(//
         "update order_return set return_goods_money =0.00 ,return_other_money = 8--149.00, return_total_fee = ifnull(return_shipping,0)+ifnull(return_other_discount,0)+0.00--149.00-0.00,return_goods_amount=1,return_real_money=0.00 where id=1319"));
 
         Assert.assertEquals(1, provider.getTableStats().size());

src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlSelectTest_15.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 1999-2011 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.bvt.sql.mysql;
+
+import java.util.List;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.sql.MysqlTest;
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.ast.statement.SQLSelect;
+import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
+import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlSchemaStatVisitor;
+import com.alibaba.druid.stat.TableStat;
+
+public class MySqlSelectTest_15 extends MysqlTest {
+
+    public void test_0() throws Exception {
+        String sql = "SELECT 1--1 from t where id = 1";
+
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement stmt = statementList.get(0);
+
+        SQLSelectStatement selectStmt = (SQLSelectStatement) stmt;
+
+        SQLSelect select = selectStmt.getSelect();
+        Assert.assertNotNull(select.getQuery());
+        MySqlSelectQueryBlock queryBlock = (MySqlSelectQueryBlock) select.getQuery();
+        Assert.assertNull(queryBlock.getOrderBy());
+
+        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
+        stmt.accept(visitor);
+
+        Assert.assertEquals(1, visitor.getTables().size());
+        Assert.assertEquals(1, visitor.getColumns().size());
+        Assert.assertEquals(1, visitor.getConditions().size());
+        Assert.assertEquals(0, visitor.getOrderByColumns().size());
+
+        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("t")));
+
+        String output = SQLUtils.toMySqlString(stmt);
+        Assert.assertEquals("SELECT 1 - -1" //
+                            + "\nFROM t" //
+                            + "\nWHERE id = 1", //
+                            output);
+    }
+}