Insert INTO queries using WHERE clause - php

Question

I have issue on INSERT INTO query,
In the registration form, when user enter username and select the department/center as bursary,
I want to insert that UserName into table bursary.
What I tried is;
$query14 = "INSERT INTO bursary (UserName) VALUES
('$UserName') WHERE DepartCent='Bursary'";
$result14=mysql_query($query14);
My table name is bursary, and it's look like ;
UserID UserName
1 ( ) <---- I want only UserName that choose department/center as bursary
Please anyone help me to solve this, appreciate that.

Answer 1

INSERT queries imply adding data that isn't there already. If you want to insert a value derived from a query you need to use an actual query to get it. The WHERE clause fails because there no row to examine until you insert one.
There's really not enough info to figure out what you're trying to do, but if we just go on this part of your question:
"I want only UserName that choose department/center as bursary"
Then you are probably looking for an INSERT..SELECT (assumes you have already inserted the data into some other user table 'your_user_table')
INSERT INTO bursary(UserName)
SELECT UserName from your_user_table
WHERE DepartCent='Bursary';

Answer 2

You can either:
insert new rows in a database table
update existing rows in a database table
Only when you are trying to change values of existing rows does it make sense to specify a WHERE clause to let the database know which values you want to change.
EDIT: Could you explain again what it is exactly that you are trying to achieve? Do you want to insert only some users filling out your form? Namely those that choose bursary as their department?
Why don't you change your table structure to something like:
Table DEPARTMENT:
Department Name, Department ID
Table USER:
User Name, Department ID (foreign key to Department)
EDIT Nr. 2: The way to do that is by normalizing your Table structure. Suppose one of the following things happened:
You want to add an additional department later on - you would not want to create a new table for that every time.
You want to change the name of a department - do you want to rename your tables? change your code,... I doubt that
So the way to go is to design your tables in a way that they separate the different "things" in your program. One type of thing you are working with are departments (bursary,...) another type of thing are Users. As a rough starting point try to make a table for each and try to connect the tables with so called foreign keys. Read it like this:
Every department has a unique department ID
Every User is associated to a department by this users Department-ID
You can then later on join these tables to find out all users of department X,...
Select u.userName,d.departmentName from User u INNER JOIN Department d ON
u.departmentId=d.departmentId
This would show you the names of all your users and their associated departmentName