support pgsql truncate statement

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

@@ -0,0 +1,36 @@
+package com.alibaba.druid.bvt.sql.postgresql;
+
+import java.util.List;
+
+import junit.framework.Assert;
+
+import com.alibaba.druid.sql.PGTest;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.postgresql.parser.PGSQLStatementParser;
+import com.alibaba.druid.sql.dialect.postgresql.visitor.PGSchemaStatVisitor;
+import com.alibaba.druid.stat.TableStat;
+import com.alibaba.druid.stat.TableStat.Column;
+
+public class TruncateTest extends PGTest {
+	public void test_0() throws Exception {
+		String sql = "TRUNCATE bigtable, fattable;";
+		
+        PGSQLStatementParser parser = new PGSQLStatementParser(sql);
+        List<SQLStatement> statementList = parser.parseStatementList();
+        SQLStatement statemen = statementList.get(0);
+        System.out.println(output(statementList));
+
+        Assert.assertEquals(1, statementList.size());
+
+        PGSchemaStatVisitor visitor = new PGSchemaStatVisitor();
+        statemen.accept(visitor);
+        
+        System.out.println("Tables : " + visitor.getTables());
+        System.out.println("fields : " + visitor.getFields());
+        
+        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("bigtable")));
+        Assert.assertTrue(visitor.getTables().containsKey(new TableStat.Name("fattable")));
+        
+        Assert.assertTrue(visitor.getFields().size() == 0);
+	}
+}