FULLTEXT索引在2个表的连接中

Question

我们是否允许在2个表的连接上使用全文索引搜索？ 这是我的疑问：

select DISTINCT table1.email from table1 
LEFT JOIN table2 ON table1.email = table2.email 
where MATCH(name,city,area,landmark,class,subject) 
      AGAINST('some text to search from');

Answer 1

假设class和subject来自table2，请使用：

WHERE IF(table2.email IS NULL,
         MATCH(name, city, area, landmark) AGAINST ('some text to search from'),
         MATCH(name, city, area, landmark, class, subject) AGAINST ('some text to search from'))

这样，当行中没有该表的数据时，它不会尝试从table2搜索列。