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sqlglot.optimizer.isolate_table_selects 

 1from sqlglot import alias, exp
 2from sqlglot.errors import OptimizeError
 3from sqlglot.optimizer.scope import traverse_scope
 4from sqlglot.schema import ensure_schema
 5
 6
 7def isolate_table_selects(expression, schema=None):
 8    schema = ensure_schema(schema)
 9
10    for scope in traverse_scope(expression):
11        if len(scope.selected_sources) == 1:
12            continue
13
14        for _, source in scope.selected_sources.values():
15            if (
16                not isinstance(source, exp.Table)
17                or not schema.column_names(source)
18                or isinstance(source.parent, exp.Subquery)
19                or isinstance(source.parent.parent, exp.Table)
20            ):
21                continue
22
23            if not source.alias:
24                raise OptimizeError("Tables require an alias. Run qualify_tables optimization.")
25
26            source.replace(
27                exp.select("*")
28                .from_(
29                    alias(source, source.alias_or_name, table=True),
30                    copy=False,
31                )
32                .subquery(source.alias, copy=False)
33            )
34
35    return expression
def isolate_table_selects(expression, schema=None): 
 8def isolate_table_selects(expression, schema=None):
 9    schema = ensure_schema(schema)
10
11    for scope in traverse_scope(expression):
12        if len(scope.selected_sources) == 1:
13            continue
14
15        for _, source in scope.selected_sources.values():
16            if (
17                not isinstance(source, exp.Table)
18                or not schema.column_names(source)
19                or isinstance(source.parent, exp.Subquery)
20                or isinstance(source.parent.parent, exp.Table)
21            ):
22                continue
23
24            if not source.alias:
25                raise OptimizeError("Tables require an alias. Run qualify_tables optimization.")
26
27            source.replace(
28                exp.select("*")
29                .from_(
30                    alias(source, source.alias_or_name, table=True),
31                    copy=False,
32                )
33                .subquery(source.alias, copy=False)
34            )
35
36    return expression