bug fixed for sql parameterized, for issue #2327

src/main/java/com/alibaba/druid/sql/visitor/SQLASTOutputVisitor.java

@@ -4352,6 +4352,10 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Paramet
     }
 
     public void printComment(String comment) {
+        if (comment == null) {
+            return;
+        }
+
         if (comment.startsWith("--") && comment.length() > 2 && comment.charAt(2) != ' ') {
             print0("-- ");
             print0(comment.substring(2));

src/test/java/com/alibaba/druid/bvt/sql/mysql/select/MySqlSelectTest_114.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 1999-2017 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.select;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlSchemaStatVisitor;
+import com.alibaba.druid.sql.visitor.ParameterizedOutputVisitorUtils;
+import com.alibaba.druid.util.JdbcConstants;
+import junit.framework.TestCase;
+
+import java.util.List;
+
+public class MySqlSelectTest_114 extends TestCase {
+
+    public void test_0() throws Exception {
+        String sql = "select count(0) from (select id from auth WHERE 1=1 AND/**/b=2 ORDER BY create_time DESC) as total";
+
+        List<SQLStatement> statementList = SQLUtils.parseStatements(sql, JdbcConstants.MYSQL);
+        assertEquals(1, statementList.size());
+        SQLSelectStatement stmt = (SQLSelectStatement) statementList.get(0);
+//        print(statementList);
+
+        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());
+        
+        assertEquals(1, visitor.getTables().size());
+        assertEquals(3, visitor.getColumns().size());
+        assertEquals(1, visitor.getConditions().size());
+        assertEquals(1, visitor.getOrderByColumns().size());
+
+        assertEquals("SELECT COUNT(0)\n" +
+                "FROM (\n" +
+                "\tSELECT id\n" +
+                "\tFROM auth\n" +
+                "\tWHERE 1 = 1\n" +
+                "\t\tAND /**/\n" +
+                "\t\tb = 2\n" +
+                "\tORDER BY create_time DESC\n" +
+                ") total", stmt.toString());
+
+        String psql = ParameterizedOutputVisitorUtils.parameterize(sql, JdbcConstants.MYSQL);
+        assertEquals("SELECT COUNT(0)\n" +
+                "FROM (\n" +
+                "\tSELECT id\n" +
+                "\tFROM auth\n" +
+                "\tWHERE 1 = 1\n" +
+                "\t\tAND \n" +
+                "\t\tb = ?\n" +
+                "\tORDER BY create_time DESC\n" +
+                ") total", psql);
+    }
+    
+    
+    
+}