database design help mysql

craptakular · 1 Feb 2012 at 20:58

Am I going to run into trouble when I join 10 tables and then attempt to select columns that aren't in all tables?

I want to select only 5 of the last rows on 10 tables, but some of the columns don't exist in all tables.

Is this a problem?

craptakular · 1 Feb 2012 at 21:44

I suppose I could select the Nth row when all tables are joined instead of worrying about this?

At most I would want to do a top10, so that's 10 separate queries I guess....

craptakular · 1 Feb 2012 at 22:11

Ok, lets say I am a project manager and I have to document how much I spend for each month a project is alive:

Project 1

Jan--Feb--Mar---timestamp
10---20---22----

Project 2

Jan--Feb--Mar--Apr----timestamp
12---08----14---15

I want to join the two tables and then something like:

while($row = mysql_fetch_array($result))
{
echo $row['Jan'];
echo " " . $row['Feb'];
echo " " . $row['Mar'];
echo " " . $row['Apr'];
echo "<br />";
}

But this will do funky things in the html as project1 doesn't have an Apr column

craptakular · 1 Feb 2012 at 22:54

it's logging bingo balls so one table that only logs one type of game might have say 8 columns ball1 up to ball8

a second table may have a game with 10balls so will have ball1 column up to ball10 column.

I want to select the last 5 rows by timestamp and print all the rows for balls 1-8 or 10 if it has more balls.

Am I making sense?

craptakular · 2 Feb 2012 at 07:16

would that not leave blank html tags?

i want to put $rows[ball1] - $rows[ball14] into <il. tags so i can style then.

ah so by checking for if its null it will remove them from the array but still print games that have it?

I guess before I print the results I need to check for null values and remove them from there $row arrays?

I could use array_filter, does this work on multi-dimensional arrays?

craptakular · 2 Feb 2012 at 12:27

I think so. I'm new to all this. The rows will be associative, so do I do foreach loop if not null