如何使用 fetchmany 将 mysql 表转储到 csv 中

Question

I have a big mysql table and I want to export it to csv file using python. However, when I use cursor.fetchall() my laptop hangs and when I use

cursor.execute("select * from table_name")
while True:
     rows = cursor.fetchmany(1000);
     while rows is not None:
         with open(table_name + ".csv", "a+") as csvfile:
             writer = csv.writer(csvfile, delimiter=',')
             writer.writerow(rows)
csvfile.close()

the loop wont stop and in the csv file the same rows are written multiple times. How to move mysql table to csv little by little? Thank you for the help.

Answer 1

you are using while loop which never ends as there is no any break condition.

Please use while loops very carefully.

You can try below code(assuming rows is the list of records):

cursor.execute("select * from table_name")
rows = cursor.fetchall()
with open(table_name + ".csv", "a+") as csvfile:
    writer = csv.writer(csvfile, delimiter=',')
    for row in rows:
        writer.writerow(row)

Answer 2

You can execute this query to output whatever table to a .CSV file on your desired location on your drive.

SELECT *
FROM tablename
INTO OUTFILE 'C:\data.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n'