Use of "Order by field" in MySQL

There is also a field in MySQL that is incrementing ( ascending - asc ), decreasing ( descending - desc ), and random ( random ) .

Field allows you to sort by sorting the items you want in one area and the proper use of MySQL's query ( search ) increases the speed.

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Use of

MySQL

1	select * from [tablo_adi] order by field([alan_adi], veri1, veri2, veri3...) [asc|desc]

After the order by field is written, the first parameter is: which field to sort on, followed by the next parameter in which order. I also note that; you can type " desc " outside the parentheses if you want to reverse the order according to the situation .

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Sample

For example, in a shopping site, sort by category name, and in doing so, use the field sort feature. In doing so, we will write 2 queries.

The first step is to take a sequence of categories;

PHP

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$sorted_cat_ids = array(); $query = mysql_query("select id from kategoriler order by ad asc"); while ($result = mysql_fetch_array($query, MYSQL_ASSOC)) { $sorted_cat_ids[] = $result["id"]; }

Now it is time to bring products;

PHP

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$query = mysql_query(sprintf('select id, ad from urunler order by field(kategori_id, %1$s)', implode(", ", $sorted_cat_ids))); while($result = mysql_fetch_array($query, MYSQL_ASSOC)) { // işlemler }

I hope the sample helps you understand better ...

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Performance

I did not do a detailed research on performance, but if I were to do construction-dismantling;