How Can I Use SQLAlchemy's VALUES Clause to Construct Queries Beyond INSERT Statements?

Working with the VALUES Clause in SQLAlchemy

The VALUES clause can be a useful tool for constructing queries in various database systems. However, SQLAlchemy's documentation primarily mentions its use in conjunction with the INSERT statement.

Building a VALUES Expression

To address this limitation, SQLAlchemy now provides the ability to construct Query objects that incorporate the VALUES clause. This functionality closely resembles the classic SQL syntax:

SELECT * FROM (VALUES (1, 2, 3)) AS sq;

In SQLAlchemy, you can achieve the same result using the following code:

from sqlalchemy import select, column, Integer
from sqlalchemy.sql import Values

select(Values(column('Number', Integer), name='sq').data([(1,), (2,), (3,)]))

This code generates a subquery that selects all columns from a virtual table (provided by the VALUES expression) named 'sq'.

Caveats and Resources

It's worth noting that this feature is not yet fully documented. However, for further exploration, you can refer to the test cases available at:

https://github.com/sqlalchemy/sqlalchemy/blob/master/test/sql/test_values.py

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