Question

我有一个sqlite3数据库。它在某些列中有一些 NULL 值。我想要的是循环遍历每一列并将 NULL 值更新为 0 ？我可以使用pandas来做，但我想知道如果可以使用sqlite3来做到这一点。如果可能的话，那么同样的命令也可以在MySQL中运行。？

代码：

import sqlite3 as sql

#connect to database
connection = sql.connect("ADARSH.db")

#make a cursor which will move in the database
cursor = connection.cursor()

#execute the different command
def execute(cursor, command):
    return cursor.execute(command)

#print the result
def print_result(result):
    for var in result:
        print(var)

# select every column name
command = """select * from emplyee where 1=0"""
result = execute(cursor, command)

# and store it in a list
col_list = [d[0] for d in result]

#for every column name, replace NULL value with 0
def update_null(cursor, col_list):
    for each_col in col_list:
        command = "update emplyee set {col_name}='0' where {col_name} is null".format(
                    col_name=each_col)
        execute(cursor, command)

update_null(cursor, col_list)
command = """select * from emplyee """
result = execute(cursor, command)
print_result(result)

此代码不会更改我的数据库中的任何内容，并且无任何错误。

Answer 1

您需要提交并关闭您打开的光标，以便在DB.Add中看到更改

connection.commit()
cursor.close()
connection.close()

最后检查更改是否反映在数据库中。

如何将列中的每个NULL值更新为零？

1 个答案: