create table field formula help

[michaelowen]

i have been looking all over the place, but i need to know how to create a field in my database table that simply adds two of the other fields?

what datatype.

i tried VARCHAR
length 5
values 'field_one'+'field_two'

what is the correct syntax?

-Michael

[lilleman]

So, let me get this straight. What you want to do is to merge the values in "field_one" and "field_two" into a new field in your table? I don't think that you can do this with just one query, I think that you have to add the field with one query and then update the table with another one.

// add the field
$sql = "ALTER TABLE tbl_name ADD field_three VARCHAR(10)";
mysql_query($sql) or die(mysql_error());

// update the table
$sql = "UPDATE tbl_name SET field_three = CONCAT(field_one, field_two)";
mysql_query($sql) or die(mysql_error());

/ Erik

[dnast]

Just add them together in the SELECT query i.e.:

SELECT field1 + field2 AS total FROM table

So if you want to query field1, field2, and their total it would be:

SELECT field1,field2,field1 + field2 AS total FROM table