query_scalar

query_scalar(sql: str, version: str | int | float | VersionInfo | None = None, *, prefix: Sequence[str] | None = None, **kwargs: Any) → Any[source]

Ensure the data is available, run the query, then extract the result.

Similar to query(), but automatically unpacks the value, assuming that only one record is returned with just a single column.

Parameters:

  • sql – A SQL query string or table name

  • version – The version number of ChEMBL to get. If none specified, uses latest() to look up the latest.

  • prefix – The directory inside pystow to use

  • kwargs – keyword arguments to pass through to pandas.read_sql(), such as index_col.

Returns:

A value (int, str, etc.) from the database.

Example: .. code-block:: python

import chembl_downloader

sql = “SELECT COUNT(activity_id) FROM activities” count: int = chembl_downloader.query_one(sql)