Method visit_select

lib/sqlalchemy/sql/compiler.py:4973–5194

(
        self,
        select_stmt,
        asfrom=False,
        insert_into=False,
        fromhints=None,
        compound_index=None,
        select_wraps_for=None,
        lateral=False,
        from_linter=None,
        **kwargs,
    )

    """

    def visit_select(
        self,
        select_stmt,
        asfrom=False,
        insert_into=False,
        fromhints=None,
        compound_index=None,
        select_wraps_for=None,
        lateral=False,
        from_linter=None,
        **kwargs,
    ):
        assert select_wraps_for is None, (
            "SQLAlchemy 1.4 requires use of "
            "the translate_select_structure hook for structural "
            "translations of SELECT objects"
        )
        if self._collect_params:
            self._add_to_params(select_stmt)

        # initial setup of SELECT.  the compile_state_factory may now
        # be creating a totally different SELECT from the one that was
        # passed in.  for ORM use this will convert from an ORM-state
        # SELECT to a regular "Core" SELECT.  other composed operations
        # such as computation of joins will be performed.

        kwargs["within_columns_clause"] = False

        compile_state = select_stmt._compile_state_factory(
            select_stmt, self, **kwargs
        )
        kwargs["ambiguous_table_name_map"] = (
            compile_state._ambiguous_table_name_map
        )

        select_stmt = compile_state.statement

        toplevel = not self.stack

        if toplevel and not self.compile_state:
            self.compile_state = compile_state

        is_embedded_select = compound_index is not None or insert_into

        # translate step for Oracle, SQL Server which often need to
        # restructure the SELECT to allow for LIMIT/OFFSET and possibly
        # other conditions
        if self.translate_select_structure:
            new_select_stmt = self.translate_select_structure(
                select_stmt, asfrom=asfrom, **kwargs
            )

            # if SELECT was restructured, maintain a link to the originals
            # and assemble a new compile state
            if new_select_stmt is not select_stmt:
                compile_state_wraps_for = compile_state
                select_wraps_for = select_stmt
                select_stmt = new_select_stmt