将数组类型的DB字段扫描到Golang中的数组/切片中

Question

tl; dr

I have an sql table users which includes an array field. How can I Scan it to variable in golang? My approach:

var id        int
var username  string
var activites []string
row := db.QueryRow("SELECT id, username, activities FROM users WHERE id = 1")
err := row.Scan(&id, &username, &activites)

Works fine for id, username.

Answer 1

As @mkopriva already pointed out, this can either be accomplished using the StringArray method or with the more flexible Array method (as it accepts an interface as the argument), both found within the "github.com/lib/pq" package.

As an aside, it is also a good practice to use prepared statements.

Full example:

var id int
var username string
var activities []string

sqlStatement := `
    SELECT
        id,
        username, 
        activities 
    FROM 
        users 
    WHERE 
        id = $1
`

stmt, err := db.Prepare(sqlStatement)
if err != nil {
    // handle err
}

defer stmt.Close()

row := stmt.QueryRow(1)

err = row.Scan(
    &id,
    &username,
    pq.Array(&activities) // used here
)

if err == sql.ErrNoRows {
    // handle err
}

if err != nil {
    // handle err
}