Sets a filter among the rows presented by proxy. The filter is defined by a filter expression
which can be any SQL valid expression using proxy's columns. For instance if proxy has the "id" and
"name" columns, then a filter can be "length(name) < 5" to filter only the rows where the length of the
name is strictly inferior to 5, or "id >= 1000 and id < 2000 order by name limit 50" to filter only the rows where the id
is between 1000 and 2000, ordered by name and limited to 50 rows.
Note about column names: real column names can be used (double quoted if necessary), but columns can also be named
"_<column number>" with column numbers starting at 1.
Note that any previous filter expression is replaced with the new filter_expr if no error occurs
(if an error occurs, then any previous filter is left unchanged).
Sets a filter among the rows presented by proxy. The filter is defined by a filter expression which can be any SQL valid expression using proxy's columns. For instance if proxy has the "id" and "name" columns, then a filter can be "length(name) < 5" to filter only the rows where the length of the name is strictly inferior to 5, or "id >= 1000 and id < 2000 order by name limit 50" to filter only the rows where the id is between 1000 and 2000, ordered by name and limited to 50 rows.
Note about column names: real column names can be used (double quoted if necessary), but columns can also be named "_<column number>" with column numbers starting at 1.
Note that any previous filter expression is replaced with the new filter_expr if no error occurs (if an error occurs, then any previous filter is left unchanged).