while() and MySQL Question

[carsonk]

Hi,

I'm wondering what would be the most efficient way to go through, loop through the first three rows of a MySQL Table, then do something different on the fourth, fifth, sixth, and change back again on the seventh. I would like this pattern to continue until all the tables are used up. I would also like to make sure it can not only end on a number that is divisible by three, like fourteen.

Thanks! 🙂

[dagon]

add a counter in side the while

if( ( $loop%3 ) == 0 ) {
//0,3,6 etc

you see it a lot 3 per table row for example

[Weedpacket]

It's usually effective to take the task of getting data out of the database, preparing it for output, and displaying it into three separate tasks:

1. Getting data out of the database

2. Preparing it for output

3. Displaying it

.

Step 1.
Get the data out of the database. You could use "LIMIT $limit" to restrict the number of records retrieved to $limit. To guarantee that you only get a multiple of three, use "LIMIT 3*$limit" so that setting $limit to 4 will get you no more than 12 records (possibly less, if fewer match). Fetch all those records from the result and store them in an array.

Step 2.
Preparing it for output. Count how many you've got, and if it's not a multiple of three, drop one or two off the end (like, for example, if you get fourteen records then discard two to leave you with twelve). [man]array_slice[/man] can be used for that. The modulus operator '%' is also good. In fact, $records = array_slice($records, 0, -(count($records) % 3)) does the counting and trimming in one statement.
Then you can group the records in threes. [man]array_chunk[/man].

Step 3.
Iterate through the array you get back from array_chunk, using the usual alternating rows idea. Only instead of having one record, you've got an array of three records. Display all three and go on to the next iteration.

Step 3.

[FFVison]

dagon;10948821 wrote:

add a counter in side the while

if( ( $loop%3 ) == 0 ) {
//0,3,6 etc

you see it a lot 3 per table row for example

Actually, if I was reading the original post correctly, I think he might want it to be more like this:

if((($loop/3)%2)==0){
//code for 0,1,2
}else if((($loop/3)%2)==1){
//code for 3,4,5
}else{
//always good to have an else in these to make sure that you don't get bad data
}

Not certain, but you might need to round the $loop/3 down before doing the %2 part, though if you are working with an int, you might not have to worry about that.