3 Answers
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Go to Learn section. Click the course name in the top. Click Discover New Courses. You'll find the SQL in the course list.
To get a first overview, Google is helpful.
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SQL is a specialised language for working with databases.
There are python modules that let you run SQL queries from within python scripts. But that goes beyond what is covered in sololearn courses.
https://www.geeksforgeeks.org/sql-using-python/
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Loads of modules like : mysql, sqlite, sqlite3 and others