Igor Tandetnik <[email protected]> wrote: > Yuzem <[email protected]> wrote: >> Suppose I have this tables: >> movies: movie,name,rating >> tags: movie,tag >> filters: filter,expression >> >> In filters I have: >> rated,rating != '' >> tagged,movie in (select movie from tags) >> >> But from the "filters" table (doesn't work): >> SELECT filter,movie FROM filters LEFT JOIN movies WHERE movie IN (SELECT >> movie FROM movie WHERE expression); > > SQLite doesn't have anything like eval(). It can't take a string from a > column, then parse and interpret it as part of a SQL > statement. > > You could probably write a custom function that would take (movie, > expression) as parameters, build a statement of the form > > select 1 from movies where movie=:movie and <expression>; > > where <expression> is replaced with the actual expression (e.g. using > sprintf), run this statement and return 1 if the statement > produces any rows and 0 otherwise. Then you could write > > SELECT filter, movie FROM filters LEFT JOIN movies WHERE checkMovie(movie, > expression);
Correction: make it SELECT filter, movie FROM filters LEFT JOIN movies ON checkMovie(movie, expression); -- Igor Tandetnik _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
