openvk/Web/Models/sql/get-correspondencies-count.tsql

SELECT COUNT(id) AS cnt FROM
(
  (
    SELECT
      recipient_id AS id
    FROM messages
    WHERE
      sender_id = ?
    AND
      sender_type = ?
  ) UNION (
    SELECT
      sender_id AS id
    FROM messages
    WHERE
      recipient_id = ?
    AND
      recipient_type = ?
  )
) dt