Listing 2: CASE Expression That Solves First Processing-Order Problem

SELECT T1.keycol,
  CASE
    WHEN T1.val NOT LIKE '%[^0-9]%'
       THEN CAST(T1.val AS INT)
  END AS intval
FROM dbo.T1
  JOIN dbo.T2
    ON T1.keycol = T2.keycol;