add db2 PageUtils support

pom.xml

@@ -527,12 +527,5 @@
 			<version>2.0.2</version>
 			<scope>test</scope>
 		</dependency>
-		
-		<dependency>
-			<groupId>com.yammer.metrics</groupId>
-			<artifactId>metrics-core</artifactId>
-			<version>2.2.0</version>
-			<scope>test</scope>
-		</dependency>
 	</dependencies>
 </project>

src/main/java/com/alibaba/druid/sql/PagerUtils.java

@@ -18,6 +18,8 @@ package com.alibaba.druid.sql;
 import java.util.List;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.SQLOrderBy;
+import com.alibaba.druid.sql.ast.SQLOver;
 import com.alibaba.druid.sql.ast.SQLStatement;
 import com.alibaba.druid.sql.ast.expr.SQLAggregateExpr;
 import com.alibaba.druid.sql.ast.expr.SQLAllColumnExpr;
@@ -86,6 +88,10 @@ public class PagerUtils {
             return limitOracle(select, dbType, offset, count);
         }
 
+        if (JdbcConstants.DB2.equals(dbType)) {
+            return limitDB2(select, dbType, offset, count);
+        }
+
         if (query instanceof SQLSelectQueryBlock) {
             return limitQueryBlock(select, dbType, offset, count);
         }
@@ -104,6 +110,53 @@ public class PagerUtils {
         throw new UnsupportedOperationException();
     }
 
+    private static String limitDB2(SQLSelect select, String dbType, int offset, int count) {
+        SQLSelectQuery query = select.getQuery();
+
+        if (query instanceof SQLSelectQueryBlock) {
+            DB2SelectQueryBlock queryBlock = (DB2SelectQueryBlock) query;
+            if (offset <= 0) {
+                queryBlock.setFirst(new SQLNumberExpr(count));
+                return SQLUtils.toSQLString(select, dbType);
+            }
+
+            SQLAggregateExpr aggregateExpr = new SQLAggregateExpr("ROW_NUMBER");
+            SQLOrderBy orderBy = select.getOrderBy();
+            if (orderBy != null) {
+                aggregateExpr.setOver(new SQLOver(orderBy));
+                select.setOrderBy(null);
+            }
+
+            queryBlock.getSelectList().add(new SQLSelectItem(aggregateExpr, "ROWNUM"));
+
+            DB2SelectQueryBlock countQueryBlock = new DB2SelectQueryBlock();
+            countQueryBlock.getSelectList().add(new SQLSelectItem(new SQLAllColumnExpr()));
+
+            countQueryBlock.setFrom(new SQLSubqueryTableSource(select, "XX"));
+
+            SQLBinaryOpExpr gt = new SQLBinaryOpExpr(new SQLIdentifierExpr("ROWNUM"), //
+                                                     SQLBinaryOperator.GreaterThan, //
+                                                     new SQLNumberExpr(offset));
+            SQLBinaryOpExpr lteq = new SQLBinaryOpExpr(new SQLIdentifierExpr("ROWNUM"), //
+                                                       SQLBinaryOperator.LessThanOrEqual, //
+                                                       new SQLNumberExpr(count + offset));
+            SQLBinaryOpExpr pageCondition = new SQLBinaryOpExpr(gt, SQLBinaryOperator.BooleanAnd, lteq);
+
+            countQueryBlock.setWhere(pageCondition);
+
+            // DB2SelectQueryBlock offsetQueryBlock = new DB2SelectQueryBlock();
+            // offsetQueryBlock.getSelectList().add(new SQLSelectItem(new SQLAllColumnExpr()));
+            // offsetQueryBlock.setFrom(new SQLSubqueryTableSource(new SQLSelect(countQueryBlock), "XXX"));
+            // offsetQueryBlock.setWhere(new SQLBinaryOpExpr(new SQLIdentifierExpr("RN"), //
+            // SQLBinaryOperator.GreaterThan, //
+            // new SQLNumberExpr(offset)));
+
+            return SQLUtils.toSQLString(countQueryBlock, dbType);
+        }
+
+        return SQLUtils.toSQLString(select, dbType);
+    }
+
     private static String limitOracle(SQLSelect select, String dbType, int offset, int count) {
         SQLSelectQuery query = select.getQuery();
 
@@ -227,7 +280,7 @@ public class PagerUtils {
         if (JdbcConstants.SQL_SERVER.equals(dbType)) {
             return new SQLServerSelectQueryBlock();
         }
-        
+
         if (JdbcConstants.DB2.equals(dbType)) {
             return new DB2SelectQueryBlock();
         }

src/main/java/com/alibaba/druid/sql/SQLUtils.java

@@ -63,6 +63,10 @@ public class SQLUtils {
         if (JdbcUtils.POSTGRESQL.equals(dbType)) {
             return toPGString(sqlObject);
         }
+        
+        if (JdbcUtils.DB2.equals(dbType)) {
+            return toDB2String(sqlObject);
+        }
 
         return toSQLServerString(sqlObject);
     }
@@ -110,6 +114,14 @@ public class SQLUtils {
         String sql = out.toString();
         return sql;
     }
+    
+    public static String toDB2String(SQLObject sqlObject) {
+        StringBuilder out = new StringBuilder();
+        sqlObject.accept(new DB2OutputVisitor(out));
+
+        String sql = out.toString();
+        return sql;
+    }
 
     public static String toSQLServerString(SQLObject sqlObject) {
         StringBuilder out = new StringBuilder();

src/main/java/com/alibaba/druid/sql/ast/SQLOver.java

@@ -26,6 +26,14 @@ public class SQLOver extends SQLObjectImpl {
 
     protected final List<SQLExpr> partitionBy      = new ArrayList<SQLExpr>();
     protected SQLOrderBy          orderBy;
+    
+    public SQLOver() {
+        
+    }
+    
+    public SQLOver(SQLOrderBy orderBy) {
+        this.setOrderBy(orderBy);
+    }
 
     @Override
     protected void accept0(SQLASTVisitor visitor) {
@@ -41,6 +49,9 @@ public class SQLOver extends SQLObjectImpl {
     }
 
     public void setOrderBy(SQLOrderBy orderBy) {
+        if (orderBy != null) {
+            orderBy.setParent(this);
+        }
         this.orderBy = orderBy;
     }
 

src/main/java/com/alibaba/druid/sql/dialect/db2/ast/DB2Object.java

@@ -0,0 +1,24 @@
+/*
+ * 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.sql.dialect.db2.ast;
+
+import com.alibaba.druid.sql.ast.SQLObject;
+import com.alibaba.druid.sql.dialect.db2.visitor.DB2ASTVisitor;
+
+
+public interface DB2Object extends SQLObject {
+    void accept0(DB2ASTVisitor visitor);
+}

src/main/java/com/alibaba/druid/sql/dialect/db2/ast/stmt/DB2SelectQueryBlock.java

@@ -15,11 +15,46 @@
  */
 package com.alibaba.druid.sql.dialect.db2.ast.stmt;
 
+import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.db2.ast.DB2Object;
+import com.alibaba.druid.sql.dialect.db2.visitor.DB2ASTVisitor;
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-public class DB2SelectQueryBlock extends SQLSelectQueryBlock {
+public class DB2SelectQueryBlock extends SQLSelectQueryBlock implements DB2Object {
+
+    private SQLExpr           first;
 
     private static final long serialVersionUID = 1L;
 
- 
+    public SQLExpr getFirst() {
+        return first;
+    }
+
+    public void setFirst(SQLExpr first) {
+        this.first = first;
+    }
+    
+    
+    @Override
+    protected void accept0(SQLASTVisitor visitor) {
+        if (visitor instanceof DB2ASTVisitor) {
+            accept0((DB2ASTVisitor) visitor);
+            return;
+        }
+
+        super.accept0(visitor);
+    }
+
+    @Override
+    public void accept0(DB2ASTVisitor visitor) {
+        if (visitor.visit(this)) {
+            acceptChild(visitor, this.selectList);
+            acceptChild(visitor, this.from);
+            acceptChild(visitor, this.where);
+            acceptChild(visitor, this.groupBy);
+            acceptChild(visitor, this.first);
+        }
+        visitor.endVisit(this);
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2ExprParser.java

@@ -1,3 +1,18 @@
+/*
+ * 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.sql.dialect.db2.parser;
 
 import com.alibaba.druid.sql.parser.Lexer;

src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2Lexer.java

@@ -1,3 +1,18 @@
+/*
+ * 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.sql.dialect.db2.parser;
 
 import java.util.HashMap;
@@ -17,6 +32,10 @@ public class DB2Lexer extends Lexer {
 
         map.putAll(Keywords.DEFAULT_KEYWORDS.getKeywords());
         
+        map.put("FETCH", Token.FETCH);
+        map.put("FIRST", Token.FIRST);
+        map.put("ONLY", Token.ONLY);
+        
         DEFAULT_DB2_KEYWORDS = new Keywords(map);
     }
 

src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2SelectParser.java

@@ -15,10 +15,11 @@
  */
 package com.alibaba.druid.sql.dialect.db2.parser;
 
+import com.alibaba.druid.sql.ast.SQLExpr;
 import com.alibaba.druid.sql.ast.SQLSetQuantifier;
 import com.alibaba.druid.sql.ast.statement.SQLSelectQuery;
-import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
 import com.alibaba.druid.sql.dialect.db2.ast.stmt.DB2SelectQueryBlock;
+import com.alibaba.druid.sql.parser.ParserException;
 import com.alibaba.druid.sql.parser.SQLExprParser;
 import com.alibaba.druid.sql.parser.SQLSelectParser;
 import com.alibaba.druid.sql.parser.Token;
@@ -49,7 +50,7 @@ public class DB2SelectParser extends SQLSelectParser {
         }
 
         accept(Token.SELECT);
-        
+
         if (lexer.token() == Token.COMMENT) {
             lexer.nextToken();
         }
@@ -74,6 +75,17 @@ public class DB2SelectParser extends SQLSelectParser {
         parseWhere(queryBlock);
 
         parseGroupBy(queryBlock);
+        
+        if (lexer.token() == Token.FETCH) {
+            lexer.nextToken();
+            accept(Token.FIRST);
+            SQLExpr first = this.exprParser.primary();
+            queryBlock.setFirst(first);
+            if (identifierEquals("ROW") || identifierEquals("ROWS")) {
+                lexer.nextToken();
+            }
+            accept(Token.ONLY);
+        }
 
         return queryRest(queryBlock);
     }

src/main/java/com/alibaba/druid/sql/dialect/db2/parser/DB2StatementParser.java

@@ -1,3 +1,18 @@
+/*
+ * 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.sql.dialect.db2.parser;
 
 import com.alibaba.druid.sql.parser.Lexer;

src/main/java/com/alibaba/druid/sql/dialect/db2/visitor/DB2ASTVisitor.java

@@ -1,8 +1,26 @@
+/*
+ * 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.sql.dialect.db2.visitor;
 
+import com.alibaba.druid.sql.dialect.db2.ast.stmt.DB2SelectQueryBlock;
 import com.alibaba.druid.sql.visitor.SQLASTVisitor;
 
-
 public interface DB2ASTVisitor extends SQLASTVisitor {
 
+    boolean visit(DB2SelectQueryBlock x);
+
+    void endVisit(DB2SelectQueryBlock x);
 }

src/main/java/com/alibaba/druid/sql/dialect/db2/visitor/DB2ASTVisitorAdapter.java

@@ -1,7 +1,33 @@
+/*
+ * 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.sql.dialect.db2.visitor;
 
+import com.alibaba.druid.sql.dialect.db2.ast.stmt.DB2SelectQueryBlock;
 import com.alibaba.druid.sql.visitor.SQLASTVisitorAdapter;
 
 public class DB2ASTVisitorAdapter extends SQLASTVisitorAdapter implements DB2ASTVisitor {
 
+    @Override
+    public boolean visit(DB2SelectQueryBlock x) {
+        return true;
+    }
+
+    @Override
+    public void endVisit(DB2SelectQueryBlock x) {
+
+    }
+
 }

src/main/java/com/alibaba/druid/sql/dialect/db2/visitor/DB2OutputVisitor.java

@@ -1,10 +1,46 @@
+/*
+ * 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.sql.dialect.db2.visitor;
 
+import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.db2.ast.stmt.DB2SelectQueryBlock;
 import com.alibaba.druid.sql.visitor.SQLASTOutputVisitor;
 
-
 public class DB2OutputVisitor extends SQLASTOutputVisitor implements DB2ASTVisitor {
+
     public DB2OutputVisitor(Appendable appender){
         super(appender);
     }
+
+    @Override
+    public boolean visit(DB2SelectQueryBlock x) {
+        this.visit((SQLSelectQueryBlock) x);
+        
+        if (x.getFirst() != null) {
+            println();
+            print("FETCH FIRST ");
+            x.getFirst().accept(this);
+            print(" ROWS ONLY");
+        }
+        
+        return false;
+    }
+
+    @Override
+    public void endVisit(DB2SelectQueryBlock x) {
+
+    }
 }

src/main/java/com/alibaba/druid/sql/dialect/db2/visitor/DB2SchemaStatVisitor.java

@@ -15,6 +15,8 @@
  */
 package com.alibaba.druid.sql.dialect.db2.visitor;
 
+import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
+import com.alibaba.druid.sql.dialect.db2.ast.stmt.DB2SelectQueryBlock;
 import com.alibaba.druid.sql.visitor.SchemaStatVisitor;
 import com.alibaba.druid.util.JdbcUtils;
 
@@ -25,4 +27,14 @@ public class DB2SchemaStatVisitor extends SchemaStatVisitor implements DB2ASTVis
         return JdbcUtils.DB2;
     }
 
+    @Override
+    public boolean visit(DB2SelectQueryBlock x) {
+        return this.visit((SQLSelectQueryBlock) x);
+    }
+
+    @Override
+    public void endVisit(DB2SelectQueryBlock x) {
+        
+    }
+
 }

src/main/java/com/alibaba/druid/wall/spi/DB2WallVisitor.java

@@ -1,3 +1,18 @@
+/*
+ * 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.wall.spi;
 
 import java.util.ArrayList;

src/test/java/com/alibaba/druid/bvt/sql/PagerUtilsTest_Limit_db2_0.java

@@ -0,0 +1,53 @@
+package com.alibaba.druid.bvt.sql;
+
+import junit.framework.TestCase;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.sql.PagerUtils;
+import com.alibaba.druid.util.JdbcConstants;
+
+public class PagerUtilsTest_Limit_db2_0 extends TestCase {
+
+    public void test_mysql_0() throws Exception {
+        String sql = "select * from t";
+        String result = PagerUtils.limit(sql, JdbcConstants.DB2, 0, 10);
+        Assert.assertEquals("SELECT *" + //
+                            "\nFROM t" + //
+                            "\nFETCH FIRST 10 ROWS ONLY", result);
+    }
+
+    public void test_mysql_1() throws Exception {
+        String sql = "select * from t";
+        String result = PagerUtils.limit(sql, JdbcConstants.DB2, 10, 10);
+        Assert.assertEquals("SELECT *"//
+                            + "\nFROM (SELECT *, ROW_NUMBER() AS ROWNUM"//
+                            + "\n\tFROM t"//
+                            + "\n\t) XX"//
+                            + "\nWHERE ROWNUM > 10"//
+                            + "\n\tAND ROWNUM <= 20", result);
+    }
+
+    public void test_mysql_2() throws Exception {
+        String sql = "select * from t where age > 100";
+        String result = PagerUtils.limit(sql, JdbcConstants.DB2, 20, 10);
+        Assert.assertEquals("SELECT *"//
+                            + "\nFROM (SELECT *, ROW_NUMBER() AS ROWNUM"//
+                            + "\n\tFROM t"//
+                            + "\n\tWHERE age > 100"//
+                            + "\n\t) XX"//
+                            + "\nWHERE ROWNUM > 20"//
+                            + "\n\tAND ROWNUM <= 30", result);
+    }
+
+    public void test_mysql_3() throws Exception {
+        String sql = "select id, name, salary from t order by id, name";
+        String result = PagerUtils.limit(sql, JdbcConstants.DB2, 20, 10);
+        Assert.assertEquals("SELECT *"//
+                            + "\nFROM (SELECT id, name, salary, ROW_NUMBER() OVER (ORDER BY id, name) AS ROWNUM"//
+                            + "\n\tFROM t"//
+                            + "\n\t) XX"//
+                            + "\nWHERE ROWNUM > 20"//
+                            + "\n\tAND ROWNUM <= 30", result);
+    }
+}

src/test/java/com/alibaba/druid/bvt/sql/db2/DB2SelectTest_0.java

@@ -0,0 +1,65 @@
+/*
+ * 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.db2;
+
+import java.util.List;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.sql.DB2Test;
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.db2.parser.DB2StatementParser;
+import com.alibaba.druid.sql.dialect.db2.visitor.DB2SchemaStatVisitor;
+import com.alibaba.druid.stat.TableStat;
+import com.alibaba.druid.util.JdbcConstants;
+
+public class DB2SelectTest_0 extends DB2Test {
+
+    public void test_0() throws Exception {
+        String sql = "SELECT * FROM DSN81010.EMP;";
+
+        DB2StatementParser parser = new DB2StatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement stmt = statementList.get(0);
+        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        DB2SchemaStatVisitor visitor = new DB2SchemaStatVisitor();
+        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(1, visitor.getColumns().size());
+        Assert.assertEquals(0, visitor.getConditions().size());
+
+        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("DSN81010.EMP")));
+
+        // Assert.assertTrue(visitor.getColumns().contains(new Column("mytable", "last_name")));
+        // Assert.assertTrue(visitor.getColumns().contains(new Column("mytable", "first_name")));
+        // Assert.assertTrue(visitor.getColumns().contains(new Column("mytable", "full_name")));
+
+        String output = SQLUtils.toSQLString(stmt, JdbcConstants.DB2);
+        Assert.assertEquals("SELECT *" //
+                            + "\nFROM DSN81010.EMP", //
+                            output);
+    }
+}

src/test/java/com/alibaba/druid/bvt/sql/db2/DB2SelectTest_1.java

@@ -0,0 +1,65 @@
+/*
+ * 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.db2;
+
+import java.util.List;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.sql.DB2Test;
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.db2.parser.DB2StatementParser;
+import com.alibaba.druid.sql.dialect.db2.visitor.DB2SchemaStatVisitor;
+import com.alibaba.druid.stat.TableStat;
+import com.alibaba.druid.util.JdbcConstants;
+
+public class DB2SelectTest_1 extends DB2Test {
+
+    public void test_0() throws Exception {
+        String sql = "SELECT * FROM DSN81010.EMP FETCH FIRST 5 ROWS ONLY;";
+
+        DB2StatementParser parser = new DB2StatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement stmt = statementList.get(0);
+        print(statementList);
+
+        Assert.assertEquals(1, statementList.size());
+
+        DB2SchemaStatVisitor visitor = new DB2SchemaStatVisitor();
+        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(1, visitor.getColumns().size());
+        Assert.assertEquals(0, visitor.getConditions().size());
+
+        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("DSN81010.EMP")));
+
+        // Assert.assertTrue(visitor.getColumns().contains(new Column("mytable", "last_name")));
+        // Assert.assertTrue(visitor.getColumns().contains(new Column("mytable", "first_name")));
+        // Assert.assertTrue(visitor.getColumns().contains(new Column("mytable", "full_name")));
+
+        String output = SQLUtils.toSQLString(stmt, JdbcConstants.DB2);
+        Assert.assertEquals("SELECT *" //
+                            + "\nFROM DSN81010.EMP", //
+                            output);
+    }
+}

src/test/java/com/alibaba/druid/sql/DB2Test.java

@@ -0,0 +1,45 @@
+/*
+ * 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.sql;
+
+import java.util.List;
+
+import junit.framework.TestCase;
+
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.db2.visitor.DB2OutputVisitor;
+
+public class DB2Test extends TestCase {
+	protected String output(List<SQLStatement> stmtList) {
+		StringBuilder out = new StringBuilder();
+		DB2OutputVisitor visitor = new DB2OutputVisitor(out);
+
+		for (SQLStatement stmt : stmtList) {
+			stmt.accept(visitor);
+		}
+
+		return out.toString();
+	}
+	
+	   protected void print(List<SQLStatement> stmtList) {
+	        String text = output(stmtList);
+	        String outputProperty = System.getProperty("druid.output");
+	        if ("false".equals(outputProperty)) {
+	            return;
+	        }
+	        System.out.println(text);
+	    }
+}