clean up SqlTop impl

Author: mythz

src/ServiceStack.OrmLite.SqlServer/SqlServer2012OrmLiteDialectProvider.cs

@@ -92,16 +92,15 @@ public override string ToSelectStatement(QueryType queryType, ModelDefinition mo
             var skip = offset ?? 0;
             if (skip > 0 || rows is > 0)
             {
-                if (queryType == QueryType.Select || (rows == 1 && offset is null or 0))
+                // Use TOP if offset is unspecified
+                if (skip == 0)
                 {
-                    // Use TOP if offset is unspecified
-                    if (offset is null or 0)
-                    {
-                        var selectType = selectExpression.StartsWithIgnoreCase("SELECT DISTINCT") ? "SELECT DISTINCT" : "SELECT";
-                        var sql = StringBuilderCache.ReturnAndFree(sb);
-                        return AddSqlServerTop(rows.GetValueOrDefault(), sql, selectType);
-                    }
+                    var sql = StringBuilderCache.ReturnAndFree(sb);
+                    return SqlTop(sql, rows.GetValueOrDefault());
+                }
 
+                if (queryType == QueryType.Select || rows == 1)
+                {
                     // ORDER BY mandatory when using OFFSET/FETCH NEXT
                     if (orderByExpression.IsEmpty())
                     {

src/ServiceStack.OrmLite.SqlServer/SqlServerOrmLiteDialectProvider.cs

@@ -583,12 +583,11 @@ public override string ToSelectStatement(QueryType queryType, ModelDefinition mo
 
             var selectType = selectExpression.StartsWithIgnoreCase("SELECT DISTINCT") ? "SELECT DISTINCT" : "SELECT";
 
-            //Temp hack for SqlServer <= 2008
+            //avoid Windowing function if unnecessary
             if (skip == 0)
             {
                 var sql = StringBuilderCache.ReturnAndFree(sb) + orderByExpression;
-
-                return AddSqlServerTop(take, sql, selectType);
+                return SqlTop(sql, take, selectType);
             }
 
             // Required because ordering is done by Windowing function
@@ -607,15 +606,17 @@ public override string ToSelectStatement(QueryType queryType, ModelDefinition mo
             return ret;
         }
 
-        protected static string AddSqlServerTop(int take, string sql, string selectType)
+        protected static string SqlTop(string sql, int take, string selectType = null)
         {
+            selectType ??= sql.StartsWithIgnoreCase("SELECT DISTINCT") ? "SELECT DISTINCT" : "SELECT";
+
             if (take == int.MaxValue)
                 return sql;
 
             if (sql.Length < "SELECT".Length)
                 return sql;
 
-            return $"{selectType} TOP {take + sql.Substring(selectType.Length)}";
+            return selectType + " TOP " + take + sql.Substring(selectType.Length);
         }
 
         //SELECT without RowNum and prefer aliases to be able to use in SELECT IN () Reference Queries