How to get all rows with keys provided in a list using SQLalchemy?

In this article, we are going to get all the rows with keys provided in a list using SQLAlchemy.

Database used:

Note: For this post, we are going to get "name", "class" and "dob" keys from the student table.

Installation:

Syntax to install SQLAlchemy:

pip install sqlalchemy pymysql

Note: pymysql is a dependency that we need to install for this post

Stepwise Implementation

Step 1 : 

The first step includes importing the module and connecting to the database. You can do that by the following code:

from sqlalchemy import create_engine

user , password , host , database = 'root' , '123' , 'localhost' , 'geeksforgeeks'
engine = create_engine(url=f'mysql+pymysql://{user}:{password}@{host}/{database}?charset=utf8')

connection = engine.connect()

Step 2 :

In the second step, we will define the table name and all the keys inside their respective variables.

table_name = 'student'
keys = ['name','class','dob']

Step 3 :

Now, firstly in SQL to get particular keys, you need to specify them in the query. 

The syntax of the SQL query is:

SELECT key1 , key2 , ..... keyN FROM table_name;

So, we will form a query in python. Firstly we will use the "join" method of python to join all the keys (separated by a comma) and then using "f-string" we will form a query following the above syntax.

So our python code for that will be:

keys_joined = ",".join(keys)
query = f'SELECT {keys_joined} FROM {table_name}'

Step 4 :

Now, finally, we will execute the query and print out all the elements in the fetched result using a for loop.

result = connection.execute(query)
for elem in result:
    print(elem)

Example:

In this example, we are combining all the above-mentioned step into a single code and then displaying all rows with keys provided in a list.

from sqlalchemy import create_engine

user , password , host , database = 'root' , '123' , 'localhost' , 'geeksforgeeks'
engine = create_engine(url=f'mysql+pymysql://{user}:{password}@{host}/{database}?charset=utf8')

connection = engine.connect()

table_name = 'student'
keys = ['name','class','dob']

keys_joined = ",".join(keys)
query = f'SELECT {keys_joined} FROM {table_name}'

result = connection.execute(query)
for elem in result:
    print(elem)

Output:

mycodenotein

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Article Tags :

• Python
• Geeks Premier League
• Geeks-Premier-League-2022
• Python-SQLAlchemy

Practice Tags :

• python