Searching in multiple columns using Full Text Search(FTS) with multiple tokens using OR operator

问题

I am using FTS for querying my database for increasing the search speed as I need to search in text description also,

When I am trying to query using single column its working fine like below

select * from productsearch where productsearch match ('prod_name:panasonic*tw*')

And also,

select * from productsearch where productsearch match ('prod_short_desc:samsung*s5*')

So, above both queries give me expected result but when I try to combine both queries using OR operator its not giving me any result

select * from productsearch where productsearch match ('prod_name:panasonic*tw* OR
                                                         prod_short_desc:samsung*s5*')

So, I want to know if I am doing anything wrong in here while using OR operator for searching multiple columns

UPDATE

Below query is working fine but that doesn't fulfill my requirement,

select * from productsearch where productsearch match ('prod_name:panasonic* OR 
                                                            prod_short_desc:samsung*')

You can see that if I remove the multiple tokens then its working fine with OR operator too.

回答1:

SQLite's FTS supports only simple prefix searches.

A query like prod_short_desc:samsung*s5* consists of two expressions, prod_short_desc:samsung* and s5*, which behave exactly the same as if you had written prod_short_desc:samsung* s5*.

If you have compiled SQLite for the enhanced query syntax, you could use a query like:

prod_short_desc:samsung* prod_short_desc:s5* OR prod_name:panasonic* prod_name:tw*

If you have compiled SQLite for the standard query syntax, you cannot use a single query for this because the OR operator's precedence is too high and cannot be modified with parentheses.

回答2:

So, I found the solution finally,

instead of searching from all the columns individually, I created a single column in the database which contains data for required columns to be searched into,

Example

I need to search in prod_name & prod_short_desc columns, so I created a column named data in database and appended the values of prod_name & prod_short_desc then looking up into only data field worked like a charm

prod_name | prod_short_desc

samsung  | samsung s5

So, now I merged the data of both the columns into one with space as a seperator

data

samsung samsung s5

And then search was very fast indeed with below query,

select * from productsearch where productsearch match ('samsung*s5*')

来源：https://stackoverflow.com/questions/26012268/searching-in-multiple-columns-using-full-text-searchfts-with-multiple-tokens-u