MySQL MATH AGAINST返回0分

Question

我已将此表格称为Names：

ID | name
-----------------
1 | nobody
2 | brian
3 | john
4 | greg 

我已经改变了表格：

ALTER TABLE Names ADD FULLTEXT index_name(name);

执行此查询时：

SELECT *, (MATCH (name) AGAINST ('brian')) As score FROM Names;

我得到以下结果：

1 | nobody | 0
2 | brian | 1.0861...
3 | john | 0
4 | greg | 0 

但是当我这样做时：

SELECT *, (MATCH (name) AGAINST ('bria')) As score FROM Name;

或者

SELECT *, (MATCH (name) AGAINST ('bria*')) As score FROM Name;

我明白了：

1 | nobody | 0
2 | brian | 0
3 | john | 0
4 | greg | 0 

brian不超过50％的查询，并且确定不是停用词，因此不确定发生了什么。