managedQuery(...)is a general query mechanism that can be used for many database objects that have ContentProviders. This may include SQLite databases, phone contacts, etc. It can only be used to “query” data and not make changes to the database.
db.execSQL(...)- a method call directly in the SQLite database and can be used to perform any SQL operation. This means that it can not only query data (SELECT), but can be used to create, modify, delete tables, as well as insert, delete rows, etc.