Deveel.Data.AggregateFunctionTests.SelectAggregate C# (CSharp) Method

        private Field SelectAggregate(string functionName, params SqlExpression[] args)
        {
            var column = new SelectColumn(SqlExpression.FunctionCall(functionName, args));
            var query = new SqlQueryExpression(new[] { column });
            query.FromClause.AddTable("APP.test_table");

            var result = AdminQuery.Select(query);

            var row = result.FirstOrDefault();
            if (row == null)
                throw new InvalidOperationException();

            return row.GetValue(0);
        }