public function whereNull($column, bool $not = false, string $appendRule = 'AND'): self
    {
        $column = $this->checkStringValue('Argument $column', $column);

        $this->where[] = new NullCriterion($column, !$not, $appendRule);
        return $this;
    }
public function whereNull($column, bool $not = false, string $appendRule = 'AND'): self
    {
        $column = $this->checkStringValue('Argument $column', $column);

        $this->where[] = new NullCriterion($column, !$not, $appendRule);
        return $this;
    }
public function whereNull ( $ column , bool $ not = false , string $ appendRule = 'AND' ) : self { $ column = $ this -> checkStringValue ( 'Argument $column' , $ column ) ; $ this -> where [ ] = new NullCriterion ( $ column , ! $ not , $ appendRule ) ; return $ this ; }
Adds a IS NULL criterion to the WHERE section.

@param string|\Closure|Query|StatementInterface $column Target column
@param bool $not Whether the rule should be NOT NULL
@param string $appendRule How the criterion should be appended to the others (SQL boolean operator name)
@return $this
@throws InvalidArgumentException
@throws InvalidReturnValueException
Adds a IS NULL criterion to the WHERE section .