MySQL and PHP linking

TiKaY

Hi, I would like to know how to select the first 20 columns in a table

I got this for now :

$sql = mysql_query("SELECT * FROM [table] WHERE [row]='example'");

I just want to select the 20 first datas in that row.

How would I change this?

Krik

$sql = mysql_query("SELECT * FROM `YourTable` ORDER BY Date ASC LIMIT 20);

bradgrafelman

The above would probably work, assuming you meant rows instead of columns (big difference :p).

Krik

That is true.

I would assume that as this is the "Newbies" forum that they wouldn't yet be making in a database that fit the criteria of the question. No offense TiKaY.

If it were "20 columns", based on the question, I am not sure I can even imagine how that table must be built. :bemused:

TiKaY

Krik;10960205 wrote:
That is true.

I would assume that as this is the "Newbies" forum that they wouldn't yet be making in a database that fit the criteria of the question. No offense TiKaY.

If it were "20 columns", based on the question, I am not sure I can even imagine how that table must be built. :bemused:

What i meant is something like this:
(if a table looks like this)

                   A            B              C
1                  aa           bb            cc
2                  aa2         bb2            cc2
3                  aa3         bb3            cc3
4                  aa4         bb4            cc4

I would need a query to select, for instance, "aa2, bb2, cc2, aa3, bb3, cc3, aa4, bb4, cc4" (selecting the (row or column) 2 to 4) is it row in this case?

Oh and I'm sorry, because I am newbie in PHP and MySQL. I just read a lot of articles that showed how to connect and use databases with PHP, but i still consider myself Newbie. I will post my threats somewhere else next time. Thanks for the warning 😉 not offended

bradgrafelman

Rows are horizontal groups, columns are vertical groups.

In the context of MySQL, your table has a defined set of columns, and you insert/retrieve/etc. rows of data from that table.

Krik

1, 2, 3, and 4 are rows. A, B and C are columns.

I assumed by your reply you want to get rows 2-4 but, per your question, based on the date column. So if "C" was the date the query I gave originally would work. Just replace "Date" with "C".

$sql = mysql_query("SELECT * FROM `YourTable` ORDER BY C ASC LIMIT 20);

Usually a query looks at one or more columns in each row. The "SELECT" in a query defines which columns you want to retreive. In your query you having it retrieve all the columns.

Then usually a WHERE will define the value that one or more columns must have in order for the row to be returned in the query. In your case I you don't need a WHERE.

The ORDER BY will sort the results by the "C" column (your table may have the date column named differently). And then I set a LIMIT so that it only grabbed the first 20 rows.

Hope that helps explain it.

Oh and I'm sorry, because I am newbie in PHP and MySQL. I just read a lot of articles that showed how to connect and use databases with PHP, but i still consider myself Newbie. I will post my threats somewhere else next time.

Don't worry about posting here. I was just pointing out my logic in why I assumed a simple answer would do. I think my later post may have confuse you, it wasn't really a reply to your original question.

EDIT: you beat me to it brad, guess I should have posted be for grabbing a sandwich

TiKaY

Krik;10960211 wrote:
1, 2, 3, and 4 are rows. A, B and C are columns.

I assumed by your reply you want to get rows 2-4 but, per your question, based on the date column. So if "C" was the date the query I gave originally would work. Just replace "Date" with "C".
$sql = mysql_query("SELECT * FROM `YourTable` ORDER BY C ASC LIMIT 20);
Usually a query looks at one or more columns in each row. The "SELECT" in a query defines which columns you want to retreive. In your query you having it retrieve all the columns.

Then usually a WHERE will define the value that one or more columns must have in order for the row to be returned in the query. In your case I you don't need a WHERE.

The ORDER BY will sort the results by the "C" column (your table may have the date column named differently). And then I set a LIMIT so that it only grabbed the first 20 rows.

Hope that helps explain it.

Don't worry about posting here. I was just pointing out my logic in why I assumed a simple answer would do. I think my later post may have confuse you, it wasn't really a reply to your original question.

EDIT: you beat me to it brad, guess I should have posted be for grabbing a sandwich

What if I add another Column, giving each row a number (1 to 200 for instance) What would be the command to select, for example, the 150th row to 173rd one? Without using the Date column.

Bilbozilla

TiKaY;10960212 wrote:
What if I add another Column, giving each row a number (1 to 200 for instance) What would be the command to select, for example, the 150th row to 173rd one? Without using the Date column.

The first column should have a name like "id" or something like that, allowing you to properly identify its contents (as in "row 1 has aa, bb, cc).

$sql = mysql_query("SELECT * FROM `YourTable` WHERE id>=150 AND id<=173);

bradgrafelman

Or, slightly better:

WHERE id BETWEEN 150 AND 173

Desdinova

 $sql = mysql_query("SELECT * FROM `YourTable` LIMIT 150, 23);

instructing the grabbing of 23 rows, starting at the 150th. This would be if the actual record count is what you want to focus on, instead of the id values.

bradgrafelman

Desdinova;10960299 wrote:
or
 $sql = mysql_query("SELECT * FROM `YourTable` LIMIT 150, 23); 
instructing the grabbing of 23 rows, starting at the 150th.

But without an ORDER BY clause, "starting at the 150th" is rather arbitrary.

Desdinova

bradgrafelman;10960300 wrote:
But without an ORDER BY clause, "starting at the 150th" is rather arbitrary.

true that. but it's more on an informational note. 🙂

johanafm

And the no-where but with limit approach also disables indexing. Finding id between ... is fast. Finding ORDER BY ... LIMIT some_high_number, whatever will be slow.

Desdinova

johanafm;10960393 wrote:
And the no-where but with limit approach also disables indexing. Finding id between ... is fast. Finding ORDER BY ... LIMIT some_high_number, whatever will be slow.

Yes but that does not mean you can always use BETWEEN. In some cases, you need the LIMIT.