bulk insert on duplicate key のクエリを作る https://play.golang.org/p/40qF3edyN1C

bulk_insert_on_duplicate_key.go

package main

import (
	"fmt"
	"strings"
)

type Value struct {
	ValA string
	ValB string
	ValC string
}

const table = "table"

func main() {
	rs := []Value{
		Value{
			ValA: "foo",
			ValB: "bar",
			ValC: "fizz",
		},
		Value{
			ValA: "foo",
			ValB: "bar",
			ValC: "fizz",
		},
		Value{
			ValA: "foo",
			ValB: "bar",
			ValC: "fizz",
		},
		Value{
			ValA: "foo",
			ValB: "bar",
			ValC: "fizz",
		},
		Value{
			ValA: "foo",
			ValB: "bar",
			ValC: "fizz",
		},
	}


	if len(rs) == 0 {
		return
	}
	
	ss := make([]string, len(rs) * 3)
	base := "INSERT INTO %s (id, valb, valc) VALUES %s ON DUPLICATE KEY UPDATE valb = VALUES(valb), valc = VALUES(valc)"
	q := fmt.Sprintf(base, table, strings.TrimRight(strings.Repeat("(?, ?, ?),", len(rs)), ","))
	for i, r := range rs {
		ss[(i*3)] = r.ValA
		ss[(i*3)+1] = r.ValB
		ss[(i*3)+2] = r.ValC
	}
	fmt.Printf("query: %s\n", q)
	fmt.Printf("value: %#v\n", ss)
}