MySQL UNION与UNION ALL

Question

我似乎无法从几个查询中获得全部结果。

我试图多次获取所有相关段落，以便找到最相关的段落。

这将返回几个不同的答案：

select paragraph from lyrics where word=-2 and song=3
UNION 
select paragraph from lyrics where word=92 and song=3
UNION 
select paragraph from lyrics where word=208 and song=3

这不会返回任何答案：

select paragraph from lyrics where word=-2 and song=3
UNION ALL
select paragraph from lyrics where word=92 and song=3
UNION ALL
select paragraph from lyrics where word=208 and song=3

我试图在select语句周围添加括号，但返回错误。

编辑：删除了第一行，我添加了它们。