Github user SQLGuyChuck commented on a diff in the pull request:
https://github.com/apache/nifi/pull/1510#discussion_r102772033
--- Diff:
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/db/impl/MSSQLDatabaseAdapter.java
---
@@ -0,0 +1,82 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.nifi.processors.standard.db.impl;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.nifi.processors.standard.db.DatabaseAdapter;
+
+/**
+ * A database adapter that generates MS SQL Compatible SQL.
+ */
+public class MSSQLDatabaseAdapter implements DatabaseAdapter {
+ @Override
+ public String getName() {
+ return "MS SQL";
+ }
+
+ @Override
+ public String getDescription() {
+ return "Generates MS SQL Compatible SQL, for version 2012 or
greater";
+ }
+
+ @Override
+ public String getSelectStatement(String tableName, String columnNames,
String whereClause, String orderByClause, Long limit, Long offset) {
+ if (StringUtils.isEmpty(tableName)) {
+ throw new IllegalArgumentException("Table name cannot be null
or empty");
+ }
+ final StringBuilder query = new StringBuilder("SELECT ");
+
+ //If this is a limit query and not a paging query then use TOP in
MS SQL
+ if (limit != null && offset == null){
+ query.append("TOP ");
--- End diff --
I think something to consider is potentially adding WITH TIES option as by
default, it won't show tie rows, I think this is true of most all of the RDMSs.
http://stackoverflow.com/questions/9629953/postgresql-equivalent-for-top-n-with-ties-limit-with-ties
is related question on this subject.
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