table name: general_info
column name: system_name
description of the problem:
I create a table above that has 5 columns and then insert data to the table.
Then, I realize that I forgot to add the column above. Then, I add the column
to this table. I start input the system_name. However, I'm unable to go back
to update the rows that did not put in the system_name's info. I try to use
this statment:
update general_info
set system_name = 'APPLE'
where system_name is NULL
and database_name = 'ORANGE'
It does not give me an error message, but it does not input the data in system_name
column. How can I update my info??