diff --git a/src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java b/src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java
index 82ef2ad0fa..1423971f0c 100644
--- a/src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java
+++ b/src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java
@@ -319,6 +319,7 @@ public SQLExpr primary() {
             case ESCAPE:
             case OVER:
             case ORDER:
+            case CONSTRAINT:
                 sqlExpr = new SQLIdentifierExpr(lexer.stringVal());
                 lexer.nextToken();
                 break;
diff --git a/src/main/java/com/alibaba/druid/sql/parser/SQLParser.java b/src/main/java/com/alibaba/druid/sql/parser/SQLParser.java
index 5e81fb552b..cd2ec7a756 100644
--- a/src/main/java/com/alibaba/druid/sql/parser/SQLParser.java
+++ b/src/main/java/com/alibaba/druid/sql/parser/SQLParser.java
@@ -193,6 +193,7 @@ protected String as() {
         switch (lexer.token()) {
             case KEY:
             case INTERVAL:
+            case CONSTRAINT:
                 alias = lexer.token().name();
                 lexer.nextToken();
                 return alias;
diff --git a/src/main/java/com/alibaba/druid/util/JdbcUtils.java b/src/main/java/com/alibaba/druid/util/JdbcUtils.java
index d1f3238462..b963faa74e 100644
--- a/src/main/java/com/alibaba/druid/util/JdbcUtils.java
+++ b/src/main/java/com/alibaba/druid/util/JdbcUtils.java
@@ -426,31 +426,30 @@ public static String getDbType(String rawUrl, String driverClassName) {
             return null;
         }
 
-        if (rawUrl.startsWith("jdbc:derby:")) {
+        if (rawUrl.startsWith("jdbc:derby:") || rawUrl.startsWith("jdbc:log4jdbc:derby:")) {
             return DERBY;
-        } else if (rawUrl.startsWith("jdbc:mysql:") || rawUrl.startsWith("jdbc:cobar:")) {
+        } else if (rawUrl.startsWith("jdbc:mysql:") || rawUrl.startsWith("jdbc:cobar:")
+                   || rawUrl.startsWith("jdbc:log4jdbc:mysql:")) {
             return MYSQL;
-        } else if (rawUrl.startsWith("jdbc:log4jdbc:")) {
-            return LOG4JDBC;
         } else if (rawUrl.startsWith("jdbc:mariadb:")) {
             return MARIADB;
-        } else if (rawUrl.startsWith("jdbc:oracle:")) {
+        } else if (rawUrl.startsWith("jdbc:oracle:") || rawUrl.startsWith("jdbc:log4jdbc:oracle:")) {
             return ORACLE;
         } else if (rawUrl.startsWith("jdbc:alibaba:oracle:")) {
             return ALI_ORACLE;
-        } else if (rawUrl.startsWith("jdbc:microsoft:")) {
+        } else if (rawUrl.startsWith("jdbc:microsoft:") || rawUrl.startsWith("jdbc:log4jdbc:microsoft:")) {
             return SQL_SERVER;
-        } else if (rawUrl.startsWith("jdbc:sqlserver:")) {
+        } else if (rawUrl.startsWith("jdbc:sqlserver:") || rawUrl.startsWith("jdbc:log4jdbc:sqlserver:")) {
             return SQL_SERVER;
-        } else if (rawUrl.startsWith("jdbc:sybase:Tds:")) {
+        } else if (rawUrl.startsWith("jdbc:sybase:Tds:") || rawUrl.startsWith("jdbc:log4jdbc:sybase:")) {
             return SYBASE;
-        } else if (rawUrl.startsWith("jdbc:jtds:")) {
+        } else if (rawUrl.startsWith("jdbc:jtds:") || rawUrl.startsWith("jdbc:log4jdbc:jtds:")) {
             return JTDS;
         } else if (rawUrl.startsWith("jdbc:fake:") || rawUrl.startsWith("jdbc:mock:")) {
             return MOCK;
-        } else if (rawUrl.startsWith("jdbc:postgresql:")) {
+        } else if (rawUrl.startsWith("jdbc:postgresql:") || rawUrl.startsWith("jdbc:log4jdbc:postgresql:")) {
             return POSTGRESQL;
-        } else if (rawUrl.startsWith("jdbc:hsqldb:")) {
+        } else if (rawUrl.startsWith("jdbc:hsqldb:") || rawUrl.startsWith("jdbc:log4jdbc:hsqldb:")) {
             return HSQL;
         } else if (rawUrl.startsWith("jdbc:db2:")) {
             return DB2;
@@ -458,13 +457,13 @@ public static String getDbType(String rawUrl, String driverClassName) {
             return "sqlite";
         } else if (rawUrl.startsWith("jdbc:ingres:")) {
             return "ingres";
-        } else if (rawUrl.startsWith("jdbc:h2:")) {
+        } else if (rawUrl.startsWith("jdbc:h2:") || rawUrl.startsWith("jdbc:log4jdbc:h2:")) {
             return H2;
         } else if (rawUrl.startsWith("jdbc:mckoi:")) {
             return "mckoi";
         } else if (rawUrl.startsWith("jdbc:cloudscape:")) {
             return "cloudscape";
-        } else if (rawUrl.startsWith("jdbc:informix-sqli:")) {
+        } else if (rawUrl.startsWith("jdbc:informix-sqli:") || rawUrl.startsWith("jdbc:log4jdbc:informix-sqli:")) {
             return "informix";
         } else if (rawUrl.startsWith("jdbc:timesten:")) {
             return "timesten";
@@ -490,6 +489,8 @@ public static String getDbType(String rawUrl, String driverClassName) {
             return JdbcConstants.DM;
         } else if (rawUrl.startsWith("jdbc:kingbase:")) {
             return JdbcConstants.KINGBASE;
+        } else if (rawUrl.startsWith("jdbc:log4jdbc:")) {
+            return LOG4JDBC;
         } else {
             return null;
         }
diff --git a/src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlSelectTest_22.java b/src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlSelectTest_22.java
new file mode 100644
index 0000000000..06a5850493
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/bvt/sql/mysql/MySqlSelectTest_22.java
@@ -0,0 +1,56 @@
+/*
+ * 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.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser;
+import com.alibaba.druid.sql.dialect.mysql.visitor.MySqlSchemaStatVisitor;
+
+public class MySqlSelectTest_22 extends MysqlTest {
+
+    public void test_0() throws Exception {
+        String sql = "select CONSTRAINT constraint from t where id = 1 order by constraint desc";
+
+        
+        MySqlStatementParser parser = new MySqlStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement statemen = statementList.get(0);
+        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        MySqlSchemaStatVisitor visitor = new MySqlSchemaStatVisitor();
+        statemen.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(2, visitor.getColumns().size());
+        Assert.assertEquals(1, visitor.getConditions().size());
+        Assert.assertEquals(1, visitor.getOrderByColumns().size());
+    }
+    
+    
+    
+}
diff --git a/src/test/java/com/alibaba/druid/util/JdbcUtilsTest.java b/src/test/java/com/alibaba/druid/util/JdbcUtilsTest.java
index 518f09ed9d..5d8ff06313 100644
--- a/src/test/java/com/alibaba/druid/util/JdbcUtilsTest.java
+++ b/src/test/java/com/alibaba/druid/util/JdbcUtilsTest.java
@@ -32,5 +32,11 @@ public void testGetDbType() {
         String dbType = JdbcUtils.getDbType(jdbcUrl, null);
         assertEquals("not support cobar driver, url like jdbc:cobar:...", JdbcConstants.MYSQL, dbType);
     }
+    
+    public void test_log4jdbc_mysql() {
+        String jdbcUrl = "jdbc:log4jdbc:mysql://localhost:8066/test";
+        String dbType = JdbcUtils.getDbType(jdbcUrl, null);
+        assertEquals("not support log4jdbc mysql, url like jdbc:log4jdbc:mysql:...", JdbcConstants.MYSQL, dbType);
+    }
 
 }