This schema layout seems a little odd to me. Maybe I'm just misunderstanding the use.

Correct me if I'm wrong here:
Each row in the "bill" table is a customer? (or some other lookup value for which you're generating the data grid?) I assume the 15 fields from your original message are the 20 fields you are describing here? The values inside the Bill table are 100% unique and point to the Value table?

You're trying to generate output that looks like this?
Category            Registered        Billed        Total
electricity_use       120,00          150,12        102,36
electricity_demand    130,00          150,12        102,36

for a particular row in the Bill table where ID=something ?

If this is true, I would consider normalizing this a bit more.
If you break the columns in your bill table out into their own table, expand your values table a bit, you could end up with something like this:

categories table:
id        category_name
1          electricity_use
2          electricity_demand
...        ...
(where id is the primary key)

bill_data table:
ID_from_original_bill_table    category_id    registered billed    total
1                                 1             120,00 150,12    102,36
1                                 2             120,00 150,12    102,36
(where (ID_from_original_bill_table, category_id) is the primary key)

And do queries like this:

SELECT c.category_name, bd.registered, bd.billed,
    FROM categories AS c
    JOIN bill_data AS bd ON
    WHERE bill_data.ID_from_original_bill_table="whatever";

Or am I still not understanding correctly what you're trying to do?

If you actually need to do a pivot you might want to look here:


On 09/19/2012 01:33 PM, Bruno Sandivilli wrote:
Sorry for the lack of explanation.

I have to model a bill table.

The bill have 20 fields.
But for each field we have: *registered* value, *billed *value and* total

So i've created an *bill* table with *20 *fields (representing the bill
fields, like: consumption, demand, etc   ), and a *bill_values* table (with
*id*,*registered*,*billed *and *total*).

I'll try to ilustrate:

Bill Table

*ID |  eletricity_use | eletricity_demand_ | eletricity_traffic_use
| eletricity_penalties *| etc ........
1         101                    102                            103


Value Table

*ID | Registered | Billed | Total*

101     120,00   150,12    102,36
102     130,00   150,12    102,36
103     150,00   150,12    102,36
104     110,00   140,12    102,36

better? Thanks!

2012/9/19 Jim Giner <>

On 9/19/2012 3:12 PM, Jim Giner wrote:

On 9/18/2012 8:52 AM, Bruno Sandivilli wrote:

Hi, i strugling to decide what is the best choice:

I have a 15 row x 3 columns Flash DataGrid, it means, for each row i
have 3
To represent this in my Database, I could:

     1. Create 2 Tables : A Values table - with 3 columns ; and a Bill
     (with 15 foreign keys, each one pointing to one row in the Values
     2. Create one Table with 45 columns (15 fields * 3 values for each

I want to know, wich is the best choice?
To manage my query, now i have a SELECT with a thousand of leftJoins.

This is the best choice?

How could I run a query wich will give all results linked, like:
( column_1_val_1, column_1_val_2, column_1_val_2,
    column_2_val_1, column_1_val_2, column_1_val_3,
   etc...) ?


  I don't get it either.
You have 15 rows with 3 cols each.  So?  Display them.  Query them.  Big

What is the real difficulty here?  I'm not seeing it.

(I don't read it as 15x3x3 - at least that's not what he said since he
said 'for each row he has 3 values')

Continuing on - why is your visual structure at this point NOT the same as
your physical structure?  I don't think you're telling us what your real
problem is here.  We need more information.  You have '15 row with 3 cols
each', ie, 'each row has 3 values'.  So - your table has 15 records in it,
each with 3 columns.  Add a key field to give each row an identity and
that's it. No?

Sorry - but again - this post is not showing me a clear problem.

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