pub fn column_values(
        &self,
        predicate: Predicate,
        columns: Selection<'_>,
        dst: BTreeMap<String, BTreeSet<String>>,
    ) -> Result<BTreeMap<String, BTreeSet<String>>> {
        let columns = match columns {
            Selection::All => {
                return UnsupportedOperation {
                    msg: "column_values does not support All columns".to_owned(),
                }
                .fail();
            }
            Selection::Some(columns) => columns,
        };

        self.table
            .column_values(&predicate, columns, dst)
            .context(TableError)
    }
/// Returns the distinct set of column values for each provided column,
/// where each returned value lives in a row matching the provided
/// predicate.
///
/// If the predicate is empty then all distinct values are returned for the
/// chunk.
///
/// `dst` is intended to allow for some more sophisticated execution,
/// wherein execution can be short-circuited for distinct values that have
/// already been found. Callers can simply provide an empty `BTreeMap` to
/// skip this behaviour.
Returns the distinct set of column values for each provided column,
where each returned value lives in a row matching the provided
predicate.

If the predicate is empty then all distinct values are returned for the
chunk.

`dst` is intended to allow for some more sophisticated execution,
wherein execution can be short-circuited for distinct values that have
already been found. Callers can simply provide an empty `BTreeMap` to
skip this behaviour.
Returns the distinct set of column values for each provided column where each returned value lives in a row matching the provided predicate . If the predicate is empty then all distinct values are returned for the chunk . ` dst ` is intended to allow for some more sophisticated execution wherein execution can be short - circuited for distinct values that have already been found . Callers can simply provide an empty ` BTreeMap ` to skip this behaviour .
pub fn column_values(
        &self,
        predicate: Predicate,
        columns: Selection<'_>,
        dst: BTreeMap<String, BTreeSet<String>>,
    ) -> Result<BTreeMap<String, BTreeSet<String>>> {
        let columns = match columns {
            Selection::All => {
                return UnsupportedOperation {
                    msg: "column_values does not support All columns".to_owned(),
                }
                .fail();
            }
            Selection::Some(columns) => columns,
        };
        self.table
            .column_values(&predicate, columns, dst)
            .context(TableError)
    }
pub fn column_values ( & self , predicate : Predicate , columns : Selection < ' _ > , dst : BTreeMap < String , BTreeSet < String > > , ) -> Result < BTreeMap < String , BTreeSet < String > > > { let columns = match columns { Selection :: All => { return UnsupportedOperation { msg : " " . to_owned ( ) , } . fail ( ) ; } Selection :: Some ( columns ) => columns , } ; self . table . column_values ( & predicate , columns , dst ) . context ( TableError ) }
Returns the distinct set of column values for each provided column,
where each returned value lives in a row matching the provided
predicate.
Returns the distinct set of column values for each provided column where each returned value lives in a row matching the provided predicate .
&self
predicate
Predicate
columns
Selection<'_>
dst
BTreeMap<String, BTreeSet<String>>
&self
predicate
Predicate
columns
Selection<'_>
dst
BTreeMap<String, BTreeSet<String>>