What methods can be used to improve the efficiency of SQL query execution?

To improve the efficiency of executing SQL queries, the following methods can be used:

• Indexing: creating indexes on columns frequently used in conditions speeds up search.
• Query optimization: avoid redundant JOINs, select only necessary fields (SELECT specific columns instead of SELECT *).
• Caching: store results of frequently executed queries.
• Batch processing: perform multiple operations in a single query if possible.
• Using prepared statements: increases performance and security.

Example of using prepared statements in Python with the sqlite3 library:

import sqlite3

conn = sqlite3.connect('example.db')
cursor = conn.cursor()

# Prepared statement with a parameter
cursor.execute('SELECT * FROM users WHERE age > ?', (30,))
rows = cursor.fetchall()

for row in rows:
    print(row)

conn.close()