PHP / SQL 从数据库中选择 id 列表并在查询中使用它

Question

Hi i made a page on my website to find quest in my database.

The method i used for now, its working but i have to update it everytime.

$demande = "SELECT * FROM quest_quest WHERE id IN (584,585,586,587,589,599,601,617,608,615,616) LIMIT ".(($cPage-1)*$perPage).",$perPage"; 

instead i would like to query my database and use the id in my query

I have a table with TagID and IDquest, i want to make a query to hold all questid and use it on my query

Example:

$questsfind = mysql_query("SELECT * FROM `quest_statetag` WHERE idTag ='8'");

I want to have a variable like that (221, 587, 1155, 1255, 5585)

$demande = "SELECT * FROM quest_quest WHERE id IN ('".$questsfind."') LIMIT ".(($cPage-1)*$perPage).",$perPage"; 

nb: Sry for my english its not my mother tongue :S

Answer 1

Not sure if I understand the question, but I believe you are looking to hold a bunch of IDs in a variable (from a query) and then create another query from that?

$first = mysql_query("SELECT * FROM quest_quest WHERE id IN (1,2,3,4)");

if( ! $first )
    die('Something went wrong...');

$ids = array();

while( $row = mysql_fetch_assoc($first) ) {
    $ids[] = $row['id'];
}

$query_ids = implode(',', $ids);

$second = mysql_query("SELECT * FROM quest_statetag WHERE idTag IN ($query_ids)");

Hope that helps...

Answer 2

first you have to convert your associative array to string

$questsfinds = implode(',', $questsfind);

Then you can try FIND_IN_SET method

SELECT * FROM quest_quest WHERE FIND_IN_SET(id,'$questsfinds');