def visit_select(self, statement: AbstractStatement):
"""convertor for select statement
Arguments:
statement {AbstractStatement} -- [input select statement]
"""
# Create a logical get node
video = statement.from_table
if video is not None:
self.visit_table_ref(video)
# Filter Operator
predicate = statement.where_clause
if predicate is not None:
# Binding the expression
bind_predicate_expr(predicate)
filter_opr = LogicalFilter(predicate)
filter_opr.append_child(self._plan)
self._plan = filter_opr
# Projection operator
select_columns = statement.target_list
# ToDO
# add support for SELECT STAR
if select_columns is not None:
# Bind the columns using catalog
bind_columns_expr(select_columns)
projection_opr = LogicalProject(select_columns)
projection_opr.append_child(self._plan)
self._plan = projection_opr
def _visit_projection(self, select_columns):
# Bind the columns using catalog
bind_columns_expr(select_columns, self._column_map)
projection_opr = LogicalProject(select_columns)
projection_opr.append_child(self._plan)
self._plan = projection_opr