1. LEFT(name , 4) as start; 
 2. CAST(SUBSTRING(name, 6, 4) AS UNSIGNED) as end;

您可以使用一些regexp匹配使查询更加健壮。

SELECT id, 
  name,
  CASE WHEN name REGEXP '^[[:digit:]]{4}[ -]' THEN CAST(LEFT(name, 4) AS UNSIGNED)
  ELSE NULL
  END AS start,
  CASE WHEN name REGEXP '^[[:digit:]]{4}-[[:digit:]]{4} ' THEN CAST(SUBSTRING(name, 6, 4) AS UNSIGNED)
  ELSE NULL
  END AS end
FROM products

输出：

id  name                                        start   end
1   1969-1972 Chevrolet Small Block             1969    1972
2   1971-1975 Chevrolet Small Block Fan Shroud  1971    1975
3   1964 Chevrolet Bumper Kit Complete          1964    (null)
4   Chevrolet Clutch And Brake Pedal Assembly   (null)  (null)

或者，如果您想：

SELECT id, 
  CASE WHEN name REGEXP '^[[:digit:]]{4}-[[:digit:]]{4} ' THEN SUBSTRING(name, 10)
       WHEN name REGEXP '^[[:digit:]]{4} ' THEN SUBSTRING(name, 6)
       ELSE name 
  END AS name,
  CASE WHEN name REGEXP '^[[:digit:]]{4}[ -]' THEN CAST(LEFT(name, 4) AS UNSIGNED)
  ELSE NULL
  END AS start,
  CASE WHEN name REGEXP '^[[:digit:]]{4}-[[:digit:]]{4} ' THEN CAST(SUBSTRING(name, 6, 4) AS UNSIGNED)
  ELSE NULL
  END AS end
FROM products

输出：

id  name                                        start   end
1   Chevrolet Small Block                       1969    1972
2   Chevrolet Small Block Fan Shroud            1971    1975
3   Chevrolet Bumper Kit Complete               1964    (null)
4   Chevrolet Clutch And Brake Pedal Assembly   (null)  (null)