Patched code sample

import psycopg2
from psycopg2 import sql

def get_schemas(conn, schema_pattern=None):
    sql_query = sql.SQL("SELECT schema_name FROM information_schema.schemata")
    
    if schema_pattern:
        sql_query += sql.SQL(" WHERE schema_name LIKE %s")
    
    with conn.cursor() as cur:
        cur.execute(sql_query, [f'{schema_pattern}%'] if schema_pattern else [])
        return cur.fetchall()

def get_tables(conn, schema_name, table_pattern=None):
    sql_query = sql.SQL("""SELECT table_name FROM information_schema.tables 
                            WHERE table_schema = %s""")
    
    if table_pattern:
        sql_query += sql.SQL(" AND table_name LIKE %s")
    
    with conn.cursor() as cur:
        cur.execute(sql_query, [schema_name, f'{table_pattern}%'] if table_pattern else [schema_name])
        return cur.fetchall()

def get_columns(conn, schema_name, table_name, column_pattern=None):
    sql_query = sql.SQL("""SELECT column_name FROM information_schema.columns 
                            WHERE table_schema = %s AND table_name = %s""")
    
    if column_pattern:
        sql_query += sql.SQL(" AND column_name LIKE %s")
    
    with conn.cursor() as cur:
        cur.execute(sql_query, [schema_name, table_name, f'{column_pattern}%'] if column_pattern else [schema_name, table_name])
        return cur.fetchall()

def main():
    try:
        conn = psycopg2.connect(
            host="your_host",
            port="your_port",
            database="your_database",
            user="your_user",
            password="your_password"
        )
        
        schemas = get_schemas(conn, 'public')
        print("Schemas:", schemas)
        
        tables = get_tables(conn, 'public', 'my_table')
        print("Tables:", tables)
        
        columns = get_columns(conn, 'public', 'my_table', 'column')
        print("Columns:", columns)

    except psycopg2.Error as e:
        print(f"Error: {e}")
    finally:
        if conn:
            conn.close()

if __name__ == '__main__':
    main()