PHP如何设置脚本以从两个字段中获取两个数字值，然后添加它们并更新到第三个字段

Question

I have a table with various fields 2 of which contain a number between 1 and 50.

I need help setting up a script that will automatically take two set fields add them and insert the total into a third field for each indivdual record for all records in the table.

I'm stuck in creating this because some records will have 0 or NULL values.

Please help :)

I've think I may be able to do this purely in SQL but the closest i found was this:

Alter table Mytable add column Keywords varchar(255);
update Mytable set Keywords = concat(Categories, ' ', Tags);

Obviously I would not need to add the column etc. Either a PHP or SQL solution would be fantastic.

Example in case I'mm not explaining this well it's confusing me a lot

Column 1 - Field Value: 20
Colum 2 - Field Value 20
Add Colum 1 + Colum 2 = 40
Insert 40 into Colum 3

Thanks

Answer 1

This should do it

UPDATE [TABLE_NAME] SET col3 = [TABLE_NAME].col1 + [TABLE_NAME].col2;

Replace [TABLE_NAME] and col1, col2, col3 with your tables and columns