我找到了正常字节顺序here的答案：

WITH RECURSIVE
  unhex(str, val, weight) AS (
    SELECT 'deadbeef', 0, 1
      UNION ALL
        SELECT 
          substr(str, 1, length(str) - 1),
          val + (instr('0123456789abcdef', substr(str, length(str), 1)) - 1) * weight,
          weight * 16
        FROM unhex WHERE length(str) > 0
  )
  SELECT val FROM unhex order by weight desc limit 1;

然后我把它修改成同样的反字节顺序：

WITH RECURSIVE unhex(str, val, weight) AS (
  SELECT 
    'efbeadde', 0, 1
  UNION ALL 
  SELECT 
    substr(str, 3), 
    val + (instr('0123456789abcdef', substr(str, 2, 1)) - 1) * weight + (instr('0123456789abcdef', substr(str, 1, 1)) - 1) * weight * 16, 
    weight * 256 
  FROM unhex WHERE length(str) > 0
)
SELECT val FROM unhex order by weight desc limit 1;