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from __future__ import annotations
import typing as t
import sqlglot
from sqlglot import Schema, exp
from sqlglot.dialects.dialect import DialectType
from sqlglot.optimizer.annotate_types import annotate_types
from sqlglot.optimizer.canonicalize import canonicalize
from sqlglot.optimizer.eliminate_ctes import eliminate_ctes
from sqlglot.optimizer.eliminate_joins import eliminate_joins
from sqlglot.optimizer.eliminate_subqueries import eliminate_subqueries
from sqlglot.optimizer.expand_multi_table_selects import expand_multi_table_selects
from sqlglot.optimizer.isolate_table_selects import isolate_table_selects
from sqlglot.optimizer.lower_identities import lower_identities
from sqlglot.optimizer.merge_subqueries import merge_subqueries
from sqlglot.optimizer.normalize import normalize
from sqlglot.optimizer.optimize_joins import optimize_joins
from sqlglot.optimizer.pushdown_predicates import pushdown_predicates
from sqlglot.optimizer.pushdown_projections import pushdown_projections
from sqlglot.optimizer.qualify_columns import qualify_columns, validate_qualify_columns
from sqlglot.optimizer.qualify_tables import qualify_tables
from sqlglot.optimizer.simplify import simplify
from sqlglot.optimizer.unnest_subqueries import unnest_subqueries
from sqlglot.schema import ensure_schema
RULES = (
lower_identities,
qualify_tables,
isolate_table_selects,
qualify_columns,
pushdown_projections,
validate_qualify_columns,
normalize,
unnest_subqueries,
expand_multi_table_selects,
pushdown_predicates,
optimize_joins,
eliminate_subqueries,
merge_subqueries,
eliminate_joins,
eliminate_ctes,
annotate_types,
canonicalize,
simplify,
)
def optimize(
expression: str | exp.Expression,
schema: t.Optional[dict | Schema] = None,
db: t.Optional[str] = None,
catalog: t.Optional[str] = None,
dialect: DialectType = None,
rules: t.Sequence[t.Callable] = RULES,
**kwargs,
):
"""
Rewrite a sqlglot AST into an optimized form.
Args:
expression: expression to optimize
schema: database schema.
This can either be an instance of `sqlglot.optimizer.Schema` or a mapping in one of
the following forms:
1. {table: {col: type}}
2. {db: {table: {col: type}}}
3. {catalog: {db: {table: {col: type}}}}
If no schema is provided then the default schema defined at `sqlgot.schema` will be used
db: specify the default database, as might be set by a `USE DATABASE db` statement
catalog: specify the default catalog, as might be set by a `USE CATALOG c` statement
dialect: The dialect to parse the sql string.
rules: sequence of optimizer rules to use.
Many of the rules require tables and columns to be qualified.
Do not remove qualify_tables or qualify_columns from the sequence of rules unless you know
what you're doing!
**kwargs: If a rule has a keyword argument with a same name in **kwargs, it will be passed in.
Returns:
sqlglot.Expression: optimized expression
"""
schema = ensure_schema(schema or sqlglot.schema, dialect=dialect)
possible_kwargs = {"db": db, "catalog": catalog, "schema": schema, **kwargs}
expression = exp.maybe_parse(expression, dialect=dialect, copy=True)
for rule in rules:
# Find any additional rule parameters, beyond `expression`
rule_params = rule.__code__.co_varnames
rule_kwargs = {
param: possible_kwargs[param] for param in rule_params if param in possible_kwargs
}
expression = rule(expression, **rule_kwargs)
return expression
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