Hvordan viser man det samlede antal af den sidste række efter filstatus?

Brug en korreleret underforespørgsel:

SELECT COUNT(DISTINCT f_bankid) AS tcount
FROM tbl_fileStatus t
WHERE ? = (SELECT f_filestatus FROM tbl_fileStatus WHERE f_bankid = t.f_bankid ORDER BY f_id DESC LIMIT 1)

Erstat ? med f_bankid du søger efter.
Se demoen .

I MySql 8.0+ kan du bruge FIRST_VALUE() vinduesfunktion:

SELECT COUNT(*) AS tcount
FROM (
  SELECT DISTINCT f_bankid, 
         FIRST_VALUE(f_filestatus) OVER (PARTITION BY f_bankid ORDER BY f_id DESC) f_filestatus
  FROM tbl_fileStatus
) t
WHERE f_filestatus = ?

Se demoen .

Hvis du vil have resultater for alle f_filestatus i 1 række:

SELECT
  SUM(f_filestatus = 1) AS tcount1,
  SUM(f_filestatus = 2) AS tcount2,
  SUM(f_filestatus = 3) AS tcount3
FROM (
  SELECT t.f_bankid, t.f_filestatus
  FROM tbl_fileStatus t
  WHERE t.f_id = (SELECT f_id FROM tbl_fileStatus WHERE f_bankid = t.f_bankid ORDER BY f_id DESC LIMIT 1)
) t

Se demoen .
Resultater:

> tcount1 | tcount2 | tcount3
> ------: | ------: | ------:
>       0 |       1 |       2