Corma supports a simple array-based query syntax everywhere that a where query is accepted. The array keys define the column, while the value specifies the value to query for. The column can optionally declare a comparison operator (=, <, >, <=, >=, <>, !=, LIKE). If an array is specified for the value it translates to an IN() clause.

$objects = $orm->findBy(MyObject::class, ['columnA'=>'A', 'columnB >'=> 10, 'columnC' => null, 'inColumn'=>[1,2,3]]);

Would translate to roughly the following SQL:

SELECT * FROM my_objects main WHERE columnA = 'A' AND columnB > 10 AND columnC IS NULL AND inColumn IN(1,2,3)

While this handles the most common use cases, you will need to work with the Doctrine QueryBuilder directly for the following scenarios:

1. Joins
2. You need an OR in your where clause
3. You need to query for more than one condition on the same column
4. Group by statements
5. Having statements

In that case you can use the Corma QueryHelper to start your query, and then manipulate the QueryBuilder in your repository methods.

/**
* @param string $value
* @return MyObject[]
*/
public function findBySomething($value)
{
    $qb = $this->queryHelper->buildSelectQuery($this->getTableName(), 'main.*', ['a.columnName'=>$value])
    $qb->join('main', AnotherObject::getTableName(), 'a', 'main.id = a.myObjectId')
        ->groupBy('main.id');
    return $this->fetchAll($qb);
}