Question

I have an sqlite query that looks like this:

db_rows = db_cursor.execute(
    "SELECT * FROM my_table"
)

# check1
for row in db_rows:
    print(row)

# check2
for row in db_rows:
    print(row)

What happens is that the first for loop outputs all the rows, and the second does not output anythng at all which I find strange. Why is that? Is there a way for me to re-use db_rows multiple times? Perhaps this is a bug?

I need this because I have some nested code (for’s and if’s) which is supposed to re-use db_rows and believe it should be faster to just re-use db_rows that should be already in memory instead of executing the query again and again for each itteration of an inner loop.

Thank you.

Answer 1

… it should be faster to just re-use db_rows that should be already in memory …

Except that it’s not in memory; it’s being pulled from the database one row at a time. Convert to a list if you want to pull the results into memory.

row_list = list(db_rows)

for row in row_list:
   ...