src/Query/Simple_Query.php
public function get_column_by( $column, $where, $value ) {

		$builder = new Builder();

		$allowed_columns = $this->table->get_columns();

		if ( ! isset( $allowed_columns[ $column ] ) ) {
			throw new InvalidColumnException( "Invalid column." );
		}

		$builder->append( new Select( "`$column`" ) );
		$builder->append( new From( $this->table->get_table_name( $this->wpdb ) ) );
		$builder->append( new Where( "`$where`", true, $this->escape_value( $where, $value ) ) );

		return $this->wpdb->get_var( trim( $builder->build() ) );
	}
public function get_column_by( $column, $where, $value ) {

		$builder = new Builder();

		$allowed_columns = $this->table->get_columns();

		if ( ! isset( $allowed_columns[ $column ] ) ) {
			throw new InvalidColumnException( "Invalid column." );
		}

		$builder->append( new Select( "`$column`" ) );
		$builder->append( new From( $this->table->get_table_name( $this->wpdb ) ) );
		$builder->append( new Where( "`$where`", true, $this->escape_value( $where, $value ) ) );

		return $this->wpdb->get_var( trim( $builder->build() ) );
	}
Retrieve a specific column's value by the the specified column / value

@since 1.0

@param string $column Var to retrieve
@param string $where
@param string $value

@return string

@throws Exception