Golang Join array interface

Question

I try to create bulk insert. I use gorm github.com/jinzhu/gorm

import (
    "fmt"
    dB "github.com/edwinlab/api/repositories"
)

func Update() error {
    tx := dB.GetWriteDB().Begin()
    sqlStr := "INSERT INTO city(code, name) VALUES (?, ?),(?, ?)"
    vals := []interface{}{}

    vals = append(vals, "XX1", "Jakarta")
    vals = append(vals, "XX2", "Bandung")

    tx.Exec(sqlStr, vals)

    tx.Commit()

    return nil
}

But I got an error:

Error 1136: Column count doesn't match value count at row 1 becuse i return wrong query
INSERT INTO city(code, name) VALUES ('XX1','Jakarta','XX2','Bandung', %!v(MISSING)),(%!v(MISSING), %!v(MISSING))

If I use manual query it works:

tx.Exec(sqlStr, "XX1", "Jakarta", "XX2", "Bandung")

It will generate:

INSERT INTO city(code, name) VALUES ('XX1', 'Jakarta'),('XX2', 'Bandung')

The problem is how to make array interface to generate string like "XX1", "Jakarta", ...

Thanks for help.

did you mean that.. you want to insert two data using one query? — Kasnady
– Kasnady, Commented Mar 21, 2016 at 7:15
yes i want insert multiple data at once my reference is stackoverflow.com/a/21112176/2486312 — user2486312
– user2486312, Commented Mar 21, 2016 at 7:17

icza · Accepted Answer · 2016-03-21 07:21:57Z

5

If you want to pass elements of a slice to a function with variadic parameter, you have to use ... to tell the compiler you want to pass all elements individually and not pass the slice value as a single argument, so simply do:

tx.Exec(sqlStr, vals...)

This is detailed in the spec: Passing arguments to ... parameters.

Tx.Exec() has the signature of:

func (tx *Tx) Exec(query string, args ...interface{}) (Result, error)

So you have to pass vals.... Also don't forget to check returned error, e.g.:

res, err := tx.Exec(sqlStr, vals...)
if err != nil {
    // handle error
}

edited Mar 21, 2016 at 7:21

answered Mar 21, 2016 at 7:19

icza

423k78 gold badges1k silver badges905 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

user2486312 Over a year ago

Thanks it work is my fault i think ... only sample :|

Collectives™ on Stack Overflow

Golang Join array interface

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related