Hi there,
I am new to mysql.
My DB has a table named tbl1 of 5 number-type fields : num1,num2,num3,num4,num5
my sql Query is as the following:

SELECT
num1,
num2,
num1+num2 AS num3,
(num3+10)*2 AS num4,
num4 / 100 AS num5,
ID
FROM tbl1

the problem is that the fields num4 and num5 return zero.WHat is wrong with my query? Please help.

Hi,

I suspect that you have entries in the table that do not contain numeric values but instead contain NULL's. This is a special case in SQL. For instance, 1+0 = 1, but 1+NULL = NULL (or undefined). If the NULL values are to be interpreted as 0 then you must explicitly state this in your query using the IFNULL function.

Also looking at your query you are calling the resulting rows with names that appear to belong to the different fields in the table. So it is not clear whether you are looking to reuse the previously calculated num3 i.e. (num1 + num2) or the value of the num3 field in the table. SQL will always use the field name and never the alias.

change this --to this --

you were a great help
it works now
but how can i use ifnull in the statement