improved sql parser.

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

@@ -28,8 +28,7 @@ import com.alibaba.druid.util.JdbcConstants;
 public class PGDeleteStatement extends SQLDeleteStatement implements PGSQLStatement {
 
     private boolean       returning;
-    private String        alias;
-    
+
     public PGDeleteStatement() {
         super (JdbcConstants.POSTGRESQL);
     }
@@ -43,15 +42,16 @@ public class PGDeleteStatement extends SQLDeleteStatement implements PGSQLStatem
     }
 
     public String getAlias() {
-        return alias;
+        if (tableSource == null) {
+            return null;
+        }
+        return tableSource.getAlias();
     }
 
     public void setAlias(String alias) {
-        this.alias = alias;
+        this.tableSource.setAlias(alias);
     }
 
-
-
     protected void accept0(SQLASTVisitor visitor) {
         accept0((PGASTVisitor) visitor);
     }
@@ -73,7 +73,6 @@ public class PGDeleteStatement extends SQLDeleteStatement implements PGSQLStatem
         cloneTo(x);
 
         x.returning = returning;
-        x.alias = alias;
 
         return x;
     }

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

@@ -163,6 +163,14 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Paramet
         this.inputParameters = parameters;
     }
 
+    /**
+     *
+     * @since 1.1.5
+     */
+    public void setOutputParameters(List<Object> parameters) {
+        this.parameters = parameters;
+    }
+
     public int getIndentCount() {
         return indentCount;
     }
@@ -2286,10 +2294,16 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Paramet
 
     public boolean visit(SQLDeleteStatement x) {
         SQLTableSource from = x.getFrom();
+        String alias = x.getAlias();
 
         if (from == null) {
             print0(ucase ? "DELETE FROM " : "delete from ");
             printTableSourceExpr(x.getTableName());
+
+            if (alias != null) {
+                print(' ');
+                print0(alias);
+            }
         } else {
             print0(ucase ? "DELETE " : "delete ");
             printTableSourceExpr(x.getTableName());

src/main/java/com/alibaba/druid/support/calcite/DDLSchema.java

@@ -18,9 +18,7 @@ package com.alibaba.druid.support.calcite;
 import com.google.common.collect.*;
 import org.apache.calcite.linq4j.tree.Expression;
 import org.apache.calcite.materialize.Lattice;
-import org.apache.calcite.schema.Function;
-import org.apache.calcite.schema.Schema;
-import org.apache.calcite.schema.SchemaPlus;
+import org.apache.calcite.schema.*;
 import org.apache.calcite.schema.Table;
 
 import java.util.Collection;
@@ -105,6 +103,11 @@ public class DDLSchema implements Schema, SchemaPlus {
         return false;
     }
 
+    @Override
+    public Schema snapshot(SchemaVersion version) {
+        return null;
+    }
+
     @Override
     public <T> T unwrap(Class<T> clazz) {
         return null;
@@ -124,12 +127,10 @@ public class DDLSchema implements Schema, SchemaPlus {
 
     }
 
-    @Override
     public boolean contentsHaveChangedSince(long lastCheck, long now) {
         return false;
     }
 
-    @Override
     public Schema snapshot(long now) {
         return null;
     }

src/main/java/com/alibaba/druid/support/calcite/DDLTable.java

@@ -18,13 +18,12 @@ package com.alibaba.druid.support.calcite;
 import com.alibaba.druid.sql.ast.statement.SQLColumnDefinition;
 import com.alibaba.druid.sql.ast.statement.SQLCreateTableStatement;
 import com.alibaba.druid.sql.ast.statement.SQLTableElement;
+import org.apache.calcite.config.CalciteConnectionConfig;
 import org.apache.calcite.rel.type.*;
 import org.apache.calcite.schema.Schema;
 import org.apache.calcite.schema.Statistic;
 import org.apache.calcite.schema.Table;
-import org.apache.calcite.sql.SqlCollation;
-import org.apache.calcite.sql.SqlIdentifier;
-import org.apache.calcite.sql.SqlIntervalQualifier;
+import org.apache.calcite.sql.*;
 import org.apache.calcite.sql.type.SqlTypeName;
 
 import java.nio.charset.Charset;
@@ -70,6 +69,16 @@ public class DDLTable implements Table, RelDataType {
         return Schema.TableType.TABLE;
     }
 
+    @Override
+    public boolean isRolledUp(String column) {
+        return false;
+    }
+
+    @Override
+    public boolean rolledUpColumnValidInsideAgg(String column, SqlCall call, SqlNode parent, CalciteConnectionConfig config) {
+        return false;
+    }
+
 
     @Override
     public boolean isStruct() {