<form action="https://api.telegram.org/botToken/sendDocument" enctype="multipart/form-data" method="post">
	<p><b>ID пользователя:</b>
	<input type="text" name="chat_id" value="123456789"></p>
	<p><b>Заголовок:</b>
	<input type="text" name="caption" value="Caption"></p>

	<p><b>Файл для отправки:</b>
	<input type="file" name="document"></p>

	<p><input type="submit" value="Отправить"></p>
</form>

declare @retVal INT, @oXML INT, @url varchar(max), @ResponseText  varchar(max)

	EXEC @retVal = sp_OACreate 'MSXML2.ServerXMLHTTP.6.0', @oXML OUTPUT
        select @url = 'https://api.telegram.org/botToken/sendDocument?chat_id=123456789&document='

	EXEC @retVal = sp_OAMethod @oXML, 'open', NULL,'post', @url + ??????????, 'false'

	EXEC @retVal = sp_OAMethod @oXML, 'send'
	EXEC @retVal = sp_OAMethod @oXML, 'responseText', @ResponseText OUTPUT

DECLARE @Boundary nvarchar(64) = N'----' + CAST(newid() AS nvarchar(64))
DECLARE @ContentType nvarchar(1000) = N'multipart/form-data; boundary=' + @Boundary

DECLARE @document nvarchar(max)

SELECT @document = '--' + @Boundary + 
N'
Content-Disposition: form-data; name="document"; filename="Тестовый файл.txt"
Content-Type: plain/text

Привет!
--' + @Boundary + '--'
	declare @url varchar(8000), @retVal INT, @oXML INT, @ResponseText nvarchar(max), @bot_token varchar(64)
	SELECT @bot_token = [value] from Constants where code = 'bot'
	select @url = 'https://api.telegram.org/bottoken/sendDocument?chat_id=123456789'


	EXEC @retVal = sp_OACreate 'MSXML2.XMLHTTP', @oXML OUTPUT

	EXEC @retVal = sp_OAMethod @oXML, 'open', NULL,'post', @url,'false'
	
	EXEC @retVal = sp_OAMethod @oXML, 'setRequestHeader',NULL, 'Connection', 'keep-alive' 
	
	EXEC @retVal = sp_OAMethod @oXML, 'setRequestHeader',NULL, 'Content-Type', @ContentType

	EXEC @retVal = sp_OAMethod @oXML, 'send', NULL, @document
		
	EXEC @retVal = sp_OAMethod @oXML, 'responseText', @ResponseText OUTPUT
		

	EXEC sp_OADestroy @oXML

	SELECT @ResponseText ResponseText