a.cs

using SQLitePCL;

public class Database
{
  protected static SQLiteConnection _db;

  public BaseDb()
  {
    if( _db == null )
    {
      _db = new SQLiteConnection( [DatabasePath] );
    }
  }
}
  
public class Phrase
{
  public int Id{ get; set; }
  public string Text{ get; set; }
}

public class TablePhrase : Database
{
  private HashSet<int> _ids;

  public TablePhrase()
  {
    SQLitePCL.raw.sqlite3_create_function( _db.Handle, "IN_SET", 3, null, InSet );
  }
  
  private void InSet( sqlite3_context ctx, object user_data, sqlite3_value[] args )
  {
    var id      = raw.sqlite3_value_int( args[ 0 ] );
    var text    = raw.sqlite3_value_text( args[ 1 ] ).utf8_to_string();
    var pattern = raw.sqlite3_value_text( args[ 2 ] ).utf8_to_string();
    
    var result = 0;

    if( _ids.Contains( id ) == true 
        && Regex.IsMatch( text, pattern ) == true )
    {
      result = 1;
    }
    
    SQLitePCL.raw.sqlite3_result_int( ctx, result );
  }
  
  public List<Phrase> InSet( HashSet<int> ids, string pattern )
  {
    _ids = ids;

    var query = $"SELECT * FROM Phrase WHERE IN_SET( id, text, {pattern} )";

    var result = _db.Query<Phrase>( query );

    _ids = null;

    return result;
  }
}