""" .. include:: ../../posts/python_sql_engine.md ---- """ from __future__ import annotations import logging import time import typing as t from sqlglot import maybe_parse from sqlglot.errors import ExecuteError from sqlglot.executor.python import PythonExecutor from sqlglot.executor.table import Table, ensure_tables from sqlglot.optimizer import optimize from sqlglot.planner import Plan from sqlglot.schema import ensure_schema logger = logging.getLogger("sqlglot") if t.TYPE_CHECKING: from sqlglot.dialects.dialect import DialectType from sqlglot.executor.table import Tables from sqlglot.expressions import Expression from sqlglot.schema import Schema def execute( sql: str | Expression, schema: t.Optional[t.Dict | Schema] = None, read: DialectType = None, tables: t.Optional[t.Dict] = None, ) -> Table: """ Run a sql query against data. Args: sql: a sql statement. schema: database schema. This can either be an instance of `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}}}} read: the SQL dialect to apply during parsing (eg. "spark", "hive", "presto", "mysql"). tables: additional tables to register. Returns: Simple columnar data structure. """ tables_ = ensure_tables(tables) if not schema: schema = { name: {column: type(table[0][column]).__name__ for column in table.columns} for name, table in tables_.mapping.items() } schema = ensure_schema(schema) if tables_.supported_table_args and tables_.supported_table_args != schema.supported_table_args: raise ExecuteError("Tables must support the same table args as schema") now = time.time() expression = optimize(sql, schema, leave_tables_isolated=True, dialect=read) logger.debug("Optimization finished: %f", time.time() - now) logger.debug("Optimized SQL: %s", expression.sql(pretty=True)) plan = Plan(expression) logger.debug("Logical Plan: %s", plan) now = time.time() result = PythonExecutor(tables=tables_).execute(plan) logger.debug("Query finished: %f", time.time() - now) return result