Question

sum

某个列字段相加

sum($table, $column, $where)

• table [string]

  表名.

• column [string]

  查询的列.

• where (optional) [array]

  WHERE 条件.

sum($table, $join, $column, $where)

• table [string]

  The table name.

• join [array]

  Table relativity for table joining.

• column [string]

  The target column will be calculated.

• where (optional) [array]

  The WHERE clause to filter records.

Return: [number] 相加的值.The type of returned data is number.

$total = $database->sum("account", "money");
echo "We have $" . $total;