Question

table.a is innodb has fields id,post_id,auther,add_date

table.b is myisam has fields post_id,title,content, fulltext key(title,content)

select * from b 
where match (title,content) 
against ('+words' in boolean mode)

this could return 12 records. when run a explain, I could see the fulltext key. But

select * from a 
inner join b 
on a.post_id = 'b.post_id' 
where match (b.title,b.content)
against ('+words' in boolean mode)
and a.auther = 'someone'
order by a.id asc

this retrun 0 result. I have checked

select id,auther,post_id from a where auther = 'someone' 

the return post_id put in mysql

select post_id from b where post_id = 'post_id from table a'

this result is exist. So where is the problem? (BTW, 2 tables post_id are all saved as varchar)

Answer 1

I suspect that you didn’t intend for the join condition to be

on a.post_id = 'b.post_id'

but rather

on a.post_id = b.post_id

(The difference being that your version will join every row of b to any row of a where a.post_id is the string "b.post_id", whereas my version will join rows of a to rows of b where their respective post_id columns are equal).