Query for build at runtime according to program condition

What points should be kept in mind while writing queries as under?

$sql=" And two=2";

$sql.=" And three=3";

$sqlquery="select * 开发者_高级运维from".$sql;

I want to make complex queries like the example

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You'd better add where 1=1 into your main query. This way you could or could not have any number of AND-joined conditions.

Like this:

$base_query = 'select * from table where 1=1';
$base_query.= 'and two = 2';
$base_query = 'and three = 3';

UPDATE: Doctrine ORM style quering:

//$em is instance of EntityManager
$qb = $em->createQueryBuilder();
$qb->select('u')
  ->from('User', 'u')
  ->where('u.id = ?1')
  ->orderBy('u.name ASC');

//you could add any part of query later
$qb->andWhere("u.name = 'John'");

$query = $qb->getQuery();
$result = $query->getResult();

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I personally preffer to do that with arrays something like that:

$where = array(); $where[] = 'Two = 2' $where[] = 'Three = 3'; $sql = implode(' AND ', $where);

Other option which i think is better to use some database absraction class / active record

Regards.