Mastering pandas - Second Edition

read_sql_query

Python supports a lot of database operations using libraries such as psycopg2 and sqlalchemy. Both of them are quite comprehensive and useful when working with databases from a Python interface. However, they have their own paraphernalia, which sometimes gets too much information for simple querying tasks. Fortunately, there is a hidden gem in pandas called read_sql_query method. It does the following:

• Runs simple queries involving select, where, and so on.
• Runs all the queries that return a table or its subset in a tabular form.
• Can't use the INSERT, UPDATE, and DELETE statements.
• The output is a DataFrame and hence all the pandas methods can be used for further data processing.

Let's look at how we can make use of this ...