Pandas read_sql with Parameters Gives `TypeError: dict is not a sequence` for PostgreSQL Database

I am trying to use parameters for SQL queries with Pandas:

import pandas as pd
from sqlalchemy import create_engine

engine = create_engine('postgresql:///mydb')
conn = engine.connect()
sql = '''
SELECT id, name, age FROM person WHERE name=%{name}s
'''

df = pd.read_sql(sql, conn, params={'name': 'John Doe'})
print(df)

From how I understand the Pandas documentation this should work. But it throws a 'Type Error: dict is not a sequence'.

The solution is to wrap the SQL in text() from SQLAlchemy and use a different placeholder syntax:

import pandas as pd
from sqlalchemy import create_engine, text

engine = create_engine('postgresql:///mydb')
conn = engine.connect()
sql = '''
SELECT id, name, age FROM person WHERE name=:name
'''

df = pd.read_sql(text(sql), conn, params={'name': 'John Doe'})
print(df)

I am fine using text() because it makes the code also independent of the backend. But what is wrong with the first approach? IMHO, it exactly follows the docs.

Solution

It is expecting parenthesis not curly brackets:

import pandas as pd
from sqlalchemy import create_engine

engine = create_engine('postgresql:///mydb')
conn = engine.connect()
sql = '''
SELECT id, name, age FROM person WHERE name=%(name)s
'''

df = pd.read_sql(sql, conn, params={'name': 'John Doe'})
print(df)