收到错误：结构文字中的未知字段[重复]

I am trying to run this code:

type NullInt64 struct {
    sql.NullInt64
}

func ToNullInt64(s string) NullInt64 {
    i, err := strconv.Atoi(s)
    return NullInt64{Int64: int64(i), Valid: err == nil}
}

but I get this error:

..\sql\sql.go:27: unknown NullInt64 field 'Int64' in struct literal
..\sql\sql.go:27: unknown NullInt64 field 'Valid' in struct literal

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To initialize the embedded sql.NullInt64, you have to write:

NullInt64{sql.NullInt64{Int64: int64(i), Valid: err == nil}}

or, if your NullInt64 struct contains other fields which you don't want to initialize explicitly, you can access the embedded field by using its type:

NullInt64{NullInt64: sql.NullInt64{Int64: int64(i), Valid: err == nil}}