framework/db/BaseActiveRecord.php
protected static function findByCondition($condition)
    {
        $query = static::find();

        if (!ArrayHelper::isAssociative($condition)) {
            // query by primary key
            $primaryKey = static::primaryKey();
            if (isset($primaryKey[0])) {
                // if condition is scalar, search for a single primary key, if it is array, search for multiple primary key values
                $condition = [$primaryKey[0] => is_array($condition) ? array_values($condition) : $condition];
            } else {
                throw new InvalidConfigException('"' . get_called_class() . '" must have a primary key.');
            }
        }

        return $query->andWhere($condition);
    }
protected static function findByCondition($condition)
    {
        $query = static::find();

        if (!ArrayHelper::isAssociative($condition)) {
            // query by primary key
            $primaryKey = static::primaryKey();
            if (isset($primaryKey[0])) {
                // if condition is scalar, search for a single primary key, if it is array, search for multiple primary key values
                $condition = [$primaryKey[0] => is_array($condition) ? array_values($condition) : $condition];
            } else {
                throw new InvalidConfigException('"' . get_called_class() . '" must have a primary key.');
            }
        }

        return $query->andWhere($condition);
    }
Finds ActiveRecord instance(s) by the given condition.
This method is internally called by [[findOne()]] and [[findAll()]].
@param mixed $condition please refer to [[findOne()]] for the explanation of this parameter
@return ActiveQueryInterface the newly created [[ActiveQueryInterface|ActiveQuery]] instance.
@throws InvalidConfigException if there is no primary key defined
@internal