Golang default return 2 decimal places

I need to export the json with default 2 decimal places for amount.

In Query i have used "SELECT FORMAT(amount, 2) from product"

type product struct {
    Amount float32 `db:"Amount"`
}

So i need if the Amount value is 99 it should export 99.00
every time it is returning 99.

I just simply retrieving data from DB and exporting like json marshal the dynamic product struct.
From DB i am getting with decimal formatted value but the decimal getting lost when we are assigning the value in struct.

NOTE :: fmt.Sprintf("%.2f", value) will not work.

To export 99.00 instead of 99 ,you can convert the amount value from int to float with specified number of decimal points.Here is a simple code with the same logic :

package main

import (
	"fmt"
)

func main() {

	amount := 99

	var desiredVal float64 = float64(amount)

	fmt.Printf("amount = %d \n", amount)

	fmt.Printf("\nnew amount= %.2f", desiredVal)

}

Output:

amount = 99 

new amount= 99.00

As stated above, the formatting needs to be done on the client side - it make sense that way.

Nevertheless here is a workaround - just create a another type with the formatted values, and marshal it:

package main

import (
	"encoding/json"
	"fmt"
)

type product struct {
	Amount float32
}

func main() {
	p := product{Amount: 99.00}

	fmt.Println(string(marshal(p)))
}

type N struct {
	Amount string
}

func NewN(p product) N {
	return N{
		Amount: fmt.Sprintf("%.2f", p.Amount),
	}
}

func marshal(p product) []byte {
	n := NewN(p)
	r, _ := json.Marshal(&n)

	return r
}

{"Amount":"99.00"}

One solution is to assign some improbable value like 7777.777 and then marshal the structure. Then do a string replace of the marshalled string i.e., replace 7777.77 with 99.00.