SQL UPDATE statement error in python code - python-3.x

Question

I am trying to write a python function that updates a postgres database. The table to be updated is given (department)
Below is the function I wrote:
def modify_dept_budget(deptName, newBudget):
connection = None
try:
connection = connector() # This is a function I wrote to connect so I can hide my credentials.
cursor1 = connection.cursor()
query1 = f"select dept_name from department"
cursor1.execute(query1)
results1 = cursor1.fetchall()
results1 = [result[0] for result in results1]
if deptName in results1:
idx = results1.index(deptName)
print(results1[idx])
cursor2 = connection.cursor()
query = f"UPDATE department SET budget = %s WHERE dept_name == {deptName}"
cursor2.execute(query, [newBudget])
cursor3 = connection.cursor()
cursor3.execute(f'SELECT * FROM department')
results2 = cursor3.fetchall()
headers = [item[0] for item in cursor3.description]
df = pd.DataFrame(data = results2, columns = headers)
print(df)
except(Exception, psycopg2.DatabaseError) as error:
print(error)
finally:
if connection:
cursor1.close()
cursor2.close()
cursor3.close()
connection.close()
When I run modify_dept_budget('Music', 85000), I get the following error:
Music
column "music" does not exist
LINE 1: ...PDATE department SET budget = 85000 WHERE dept_name == Music
^
---------------------------------------------------------------------------
UnboundLocalError Traceback (most recent call last)
<ipython-input-77-16e7278e3358> in <module>
----> 1 modify_dept_budget('Music', 85000)
<ipython-input-76-80361b6ddf35> in modify_dept_budget(deptName, newBudget)
26 cursor1.close()
27 cursor2.close()
---> 28 cursor3.close()
29 connection.close()
UnboundLocalError: local variable 'cursor3' referenced before assignment
Can anyone help me figure out what is going on?

Answer 1

You have two problems. First, SQL does not use the double == for the equality test. Just plain =. Second, that string literal needs to be quoted. Unless you need a table name or a field name, you won't be using f-strings with SQL. So, do:
query = "UPDATE department SET budget = %s WHERE dept_name = %s"
cursor2.execute(query, [newBudget, deptName])