How to query an external content FTS4 table but return additional columns from the original content table

Question

I am creating an FTS4 external content table in SQLite like this:

CREATE TABLE t2(id INTEGER PRIMARY KEY, col_a, col_b, col_text);
CREATE VIRTUAL TABLE fts_t         


        

Answer 1

FTS tables have an internal INTEGER PRIMARY KEY column called docid or rowid. When inserting a row in the FTS table, set that column to the primary key of the row in the original table.

Then you can easily look up the corresponding row, either with a separate query, or with a join like this:

SELECT *
FROM t2
WHERE id IN (SELECT docid
             FROM fts_table
             WHERE col_text MATCH 'something')