# sqlglot.optimizer.isolate_table_selects API documentation

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# sqlglot.optimizer.isolate_table_selects

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     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): View Source

     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