improved pg sql parser. for issue #2309

src/main/java/com/alibaba/druid/sql/dialect/postgresql/ast/stmt/PGConnectToStatement.java

@@ -0,0 +1,45 @@
+package com.alibaba.druid.sql.dialect.postgresql.ast.stmt;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLName;
+import com.alibaba.druid.sql.ast.SQLStatementImpl;
+import com.alibaba.druid.sql.dialect.postgresql.visitor.PGASTVisitor;
+import com.alibaba.druid.sql.visitor.SQLASTOutputVisitor;
+import com.alibaba.druid.sql.visitor.SQLASTVisitor;
+import com.alibaba.druid.util.JdbcConstants;
+
+public class PGConnectToStatement extends SQLStatementImpl implements PGSQLStatement {
+    private SQLName target;
+
+    public PGConnectToStatement() {
+        super(JdbcConstants.POSTGRESQL);
+    }
+
+    protected void accept0(SQLASTVisitor visitor) {
+        this.accept0((PGASTVisitor) visitor);
+    }
+
+    public void output(StringBuffer buf) {
+        SQLASTOutputVisitor visitor = SQLUtils.createOutputVisitor(buf, dbType);
+        this.accept(visitor);
+    }
+
+    @Override
+    public void accept0(PGASTVisitor v) {
+        if (v.visit(this)) {
+            acceptChild(v, target);
+        }
+        v.endVisit(this);
+    }
+
+    public SQLName getTarget() {
+        return target;
+    }
+
+    public void setTarget(SQLName x) {
+        if (x != null) {
+            x.setParent(this);
+        }
+        this.target = x;
+    }
+}

src/main/java/com/alibaba/druid/sql/dialect/postgresql/visitor/PGASTVisitor.java

@@ -106,7 +106,9 @@ public interface PGASTVisitor extends SQLASTVisitor {
     boolean visit(PGShowStatement x);
 
     void endVisit(PGStartTransactionStatement x);
-    
     boolean visit(PGStartTransactionStatement x);
 
+    void endVisit(PGConnectToStatement x);
+    boolean visit(PGConnectToStatement x);
+
 }

src/main/java/com/alibaba/druid/sql/dialect/postgresql/visitor/PGASTVisitorAdapter.java

@@ -257,4 +257,14 @@ public class PGASTVisitorAdapter extends SQLASTVisitorAdapter implements PGASTVi
         return true;
     }
 
+    @Override
+    public void endVisit(PGConnectToStatement x) {
+
+    }
+
+    @Override
+    public boolean visit(PGConnectToStatement x) {
+        return true;
+    }
+
 }

src/main/java/com/alibaba/druid/sql/dialect/postgresql/visitor/PGOutputVisitor.java

@@ -651,6 +651,18 @@ public class PGOutputVisitor extends SQLASTOutputVisitor implements PGASTVisitor
         return false;
     }
 
+    @Override
+    public void endVisit(PGConnectToStatement x) {
+
+    }
+
+    @Override
+    public boolean visit(PGConnectToStatement x) {
+        print0(ucase ? "CONNECT TO " : "connect to ");
+        x.getTarget().accept(this);
+        return false;
+    }
+
     @Override
     public boolean visit(SQLSetStatement x) {
         print0(ucase ? "SET " : "set ");

src/main/java/com/alibaba/druid/sql/dialect/postgresql/visitor/PGSchemaStatVisitor.java

@@ -339,4 +339,14 @@ public class PGSchemaStatVisitor extends SchemaStatVisitor implements PGASTVisit
         return false;
     }
 
+    @Override
+    public void endVisit(PGConnectToStatement x) {
+
+    }
+
+    @Override
+    public boolean visit(PGConnectToStatement x) {
+        return false;
+    }
+
 }

src/test/java/com/alibaba/druid/bvt/sql/postgresql/PGConnectTo_0.java

@@ -0,0 +1,33 @@
+/*
+ * 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.postgresql;
+
+import com.alibaba.druid.sql.PGTest;
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.util.JdbcConstants;
+
+import java.util.List;
+
+public class PGConnectTo_0 extends PGTest {
+    public void testConnectTo() throws Exception {
+        List<SQLStatement> stmtList = SQLUtils.parseStatements("CONNECT to db_2", JdbcConstants.POSTGRESQL);
+        assertEquals(1, stmtList.size());
+
+        SQLStatement stmt = stmtList.get(0);
+        assertEquals("CONNECT TO db_2", stmt.toString());
+    }
+}