# Sum系列方法 求和数据可以使用`Sum`, `SumInt`, `Sums` 和 `SumsInt` 四个方法，Sums系列方法的参数为struct的指针并且成为查询条件。 * Sum 求某个字段的和，返回float64 ~~~ type SumStruct struct { Id int64 Money int Rate float32 } ss := new(SumStruct) total, err := engine.Where("id >?", 1).Sum(ss, "money") fmt.Printf("money is %d", int(total)) ~~~ * SumInt 求某个字段的和，返回int64 ~~~ type SumStruct struct { Id int64 Money int Rate float32 } ss := new(SumStruct) total, err := engine.Where("id >?", 1).SumInt(ss, "money") fmt.Printf("money is %d", total) ~~~ * Sums 求某几个字段的和， 返回float64的Slice ~~~ ss := new(SumStruct) totals, err := engine.Where("id >?", 1).Sums(ss, "money", "rate") fmt.Printf("money is %d, rate is %.2f", int(total[0]), total[1]) ~~~ * SumsInt 求某几个字段的和， 返回int64的Slice ~~~ ss := new(SumStruct) totals, err := engine.Where("id >?", 1).SumsInt(ss, "money") fmt.Printf("money is %d", total[0]) ~~~