def select_from(self, clause):
- """return a new exists() construct with the given expression set as
+ """return a new :class:`._Exists` construct, applying the given expression
+ to the :meth:`.Select.select_from` method of the select statement
def select_from(self, fromclause):
- """return a new select() construct with the given FROM expression
- applied to its list of FROM objects.
+ """return a new :class:`.Select` construct with the given FROM expression
+ merged into its list of FROM objects.
+ The "from" list is a unique set on the identity of each element,
+ so adding an already present :class:`.Table` or other selectable
+ will have no effect. Passing a :class:`.Join` that refers
+ to an already present :class:`.Table` or other selectable will have
+ the effect of concealing the presence of that selectable as
+ an individual element in the rendered FROM list, instead rendering it into a