Introduce the columnar option for SQL REST requests. (#3984)

Implements elastic/elasticsearch#39287

src/Nest/XPack/Sql/QuerySql/QuerySqlRequest.cs

@@ -15,8 +15,15 @@ public partial interface IQuerySqlRequest : ISqlRequest
 		/// Unlike scroll, receiving the last page is enough to guarantee that the Elasticsearch state is cleared.
 		/// </para>
 		/// </summary>
-		[DataMember(Name ="cursor")]
+		[DataMember(Name="cursor")]
 		string Cursor { get; set; }
+
+		/// <summary>
+		/// Return the results in a columnar fashion: one row represents all the values of a certain column from the current page of results.
+		/// The following formats can be returned in columnar orientation: json, yaml, cbor and smile.
+		/// </summary>
+		[DataMember(Name="columnar")]
+		bool? Columnar { get; set; }
 	}
 
 	public partial class QuerySqlRequest
@@ -25,6 +32,10 @@ public partial class QuerySqlRequest
 		/// >
 		public string Cursor { get; set; }
 
+		/// <inheritdoc cref="IQuerySqlRequest.Columnar" />
+		/// >
+		public bool? Columnar { get; set; }
+
 		/// <inheritdoc cref="ISqlRequest.FetchSize" />
 		/// >
 		public int? FetchSize { get; set; }
@@ -45,6 +56,7 @@ public partial class QuerySqlRequest
 	public partial class QuerySqlDescriptor
 	{
 		string IQuerySqlRequest.Cursor { get; set; }
+		bool? IQuerySqlRequest.Columnar { get; set; }
 		int? ISqlRequest.FetchSize { get; set; }
 		QueryContainer ISqlRequest.Filter { get; set; }
 		string ISqlRequest.Query { get; set; }
@@ -70,5 +82,9 @@ public QuerySqlDescriptor Filter<T>(Func<QueryContainerDescriptor<T>, QueryConta
 		/// <inheritdoc cref="IQuerySqlRequest.Cursor" />
 		/// >
 		public QuerySqlDescriptor Cursor(string cursor) => Assign(cursor, (a, v) => a.Cursor = v);
+
+		/// <inheritdoc cref="IQuerySqlRequest.Columnar" />
+		/// >
+		public QuerySqlDescriptor Columnar(bool? columnar = true) => Assign(columnar, (a, v) => a.Columnar = v);
 	}
 }

src/Nest/XPack/Sql/QuerySql/QuerySqlResponse.cs

@@ -20,7 +20,16 @@ public class QuerySqlResponse : ResponseBase
 		[DataMember(Name = "cursor")]
 		public string Cursor { get; internal set; }
 
+		/// <summary>
+		/// If <see cref="IQuerySqlRequest.Columnar"/> has been set to false, this property will contain the row values
+		/// </summary>
 		[DataMember(Name = "rows")]
 		public IReadOnlyCollection<SqlRow> Rows { get; internal set; } = EmptyReadOnly<SqlRow>.Collection;
+
+		/// <summary>
+		/// If <see cref="IQuerySqlRequest.Columnar"/> has been set to true, this property will contain the column values
+		/// </summary>
+		[DataMember(Name = "values")]
+		public IReadOnlyCollection<SqlRow> Values { get; internal set; } = EmptyReadOnly<SqlRow>.Collection;
 	}
 }