Behavior Changes on SELECT

Question

I'm migrating a SQL Server 2008 database to SQL Server 2019, I have used Microsoft Data Migration Assistant, to look for search any behavior changes, issues or syntax errors.

I have a SELECT that gives me compatibility errors to do the migration:

Object uses the old style join syntax which can have poor performance at database compatibility level 90 and higher.

This is my SELECT that I think makes the error:

SELECT 
    @Pro = CEILING((BaseDev * 100) / (ISNULL(BaseExe, 0) + ISNULL(BaseDev, 0)))
FROM 
    (SELECT SUM(Base) 'BaseDev'
     FROM Table1
     WHERE Con = @Con AND Lib <> 0 AND Tip = 1 
       AND Fac = 'V' AND ISNULL(Pct, 0) <> 0) A,
    (SELECT SUM(Base) 'BaseExe'
     FROM Table1
     WHERE Con = @Con AND Lib <> 0 AND Tip = 1 AND Fac = 'V' 
       AND ISNULL(Pct, 0) = 0) B

Answer 1

  SELECT @Pro = CEILING((A.BaseDev * 100) / (ISNULL(B.BaseExe, 0) + ISNULL(A.BaseDev, 0)))
   FROM 
   (
       SELECT SUM(Base) AS BaseDev
        FROM Table1
        WHERE Con = @Con AND Lib <> 0 AND Tip = 1 AND Fac = 'V' AND ISNULL(Pct, 0) <> 0
   ) A
  CROSS JOIN 
   (
       SELECT SUM(Base) AS BaseExe
       FROM Table1
       WHERE Con = @Con AND Lib <> 0 AND Tip = 1 AND Fac = 'V' AND ISNULL(Pct, 0) = 0
   ) B

I guess you can replace your query with this one