How to Obtain the True SQL Query in SQLAlchemy?

SQLAlchemy: Unveiling the True Query

When working with SQLAlchemy, it can be valuable to inspect the actual SQL queries being executed. While SQLAlchemy usually relies on bind parameters, there are ways to generate the corresponding SQL statements, including the actual values.

General Solution

In most cases, you can easily obtain the SQL string representation of a SQLAlchemy statement or query:

<code class="python">import sqlalchemy as sa
print(str(statement))</code>

This works for both ORM Queries and select() or other statements. If necessary, you can compile the statement to a specific dialect or engine:

<code class="python">print(statement.compile(someengine))</code>

or without specifying an engine:

<code class="python">from sqlalchemy.dialects import postgresql
print(statement.compile(dialect=postgresql.dialect()))</code>

Inlining Bound Parameters

To include the actual values instead of bind parameters in the SQL string, SQLAlchemy provides limited support through the 'literal_binds' flag in compile_kwargs:

<code class="python">from sqlalchemy import table, column, select
t = table('t', column('x'))
s = select([t]).where(t.c.x == 5)
print(s.compile(compile_kwargs={"literal_binds": True}))</code>

However, this approach only works for basic types and may not handle bind parameters without pre-assigned values. For custom types, you can implement a TypeDecorator with a process_literal_param method:

<code class="python">class MyFancyType(TypeDecorator):
    def process_literal_param(self, value, dialect):
        return "my_fancy_formatting(%s)" % value</code>

This allows you to customize the rendering of values based on your specific requirements.

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