odps/df/backends/odpssql/rewriter.py [36:69]:
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    def visit_join(self, expr):
        if expr._predicate and isinstance(expr._predicate, list):
            expr._predicate = reduce(operator.and_, expr._predicate)

        for node in (expr.rhs,):
            parents = self._parents(node)
            if isinstance(node, JoinCollectionExpr):
                projection = JoinProjectCollectionExpr(
                    _input=node, _schema=node.schema,
                    _fields=node._fetch_fields())
                self._sub(node, projection, parents)
            elif isinstance(node, JoinProjectCollectionExpr):
                self._sub(node.input, node, parents)

        need_project = [False, ]

        def walk(node):
            if isinstance(node, JoinCollectionExpr) and \
                    node.column_conflict:
                need_project[0] = True
                return

            if isinstance(node, JoinCollectionExpr):
                walk(node.lhs)

        walk(expr)

        if need_project[0]:
            parents = self._parents(expr)
            if not parents or \
                    not any(isinstance(parent, (ProjectCollectionExpr, JoinCollectionExpr))
                            for parent in parents):
                to_sub = expr[expr]
                self._sub(expr, to_sub, parents)
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