bug fixed for msyql parser. issue alibaba#1359

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

@@ -254,6 +254,12 @@ public void scanIdentifier() {
                 ch = charAt(++pos);
 
                 if (!isIdentifierChar(ch)) {
+                    if (ch == '-' && pos < text.length() - 1) {
+                        char next_char = text.charAt(pos + 1);
+                        if (isIdentifierChar(next_char)) {
+                            continue;
+                        }
+                    }
                     if (last_ch == '-' && charAt(pos-2) != '-') {
                         ch = last_ch;
                         bufPos--;
@@ -419,7 +425,7 @@ public void scanComment() {
         }
         // identifierFlags['`'] = true;
         identifierFlags['_'] = true;
-        identifierFlags['-'] = true; // mysql
+        //identifierFlags['-'] = true; // mysql
     }
 
     public static boolean isIdentifierChar(char c) {

src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlTruncateTest_1.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 1999-2101 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 com.alibaba.druid.sql.MysqlTest;
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlSchemaStatVisitor;
+import org.junit.Assert;
+
+import java.util.List;
+
+public class MySqlTruncateTest_1 extends MysqlTest {
+
+    public void test_0() throws Exception {
+        String sql = "truncate table city_list--test";
+
+
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement stmt = statementList.get(0);
+        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
+        stmt.accept(visitor);
+
+//        System.out.println("Tables : " + visitor.getTables());
+//        System.out.println("fields : " + visitor.getColumns());
+//        System.out.println("coditions : " + visitor.getConditions());
+//        System.out.println("orderBy : " + visitor.getOrderByColumns());
+
+        Assert.assertEquals(1, visitor.getTables().size());
+        Assert.assertEquals(0, visitor.getColumns().size());
+        Assert.assertEquals(0, visitor.getConditions().size());
+        Assert.assertEquals(0, visitor.getOrderByColumns().size());
+
+        {
+            String output = SQLUtils.toMySqlString(stmt);
+            Assert.assertEquals("TRUNCATE TABLE city_list", //
+                                output);
+        }
+        {
+            String output = SQLUtils.toMySqlString(stmt, SQLUtils.DEFAULT_LCASE_FORMAT_OPTION);
+            Assert.assertEquals("truncate table city_list", //
+                                output);
+        }
+    }
+
+
+
+}