如何将pq.Int64Array转换为字符串？

Question

In Golang application I make sql query to PostgreSQL database which return me array of int.

var identifiers [] pq.Int64Array

// Execute SQL query by "database/sql" package.
if err := database.DBSQL.QueryRow(sqlStatement.String()).Scan(&identifiers); err != nil {
    log.Println(err)
    utils.ResponseWithError(responseWriter, http.StatusInternalServerError, err.Error())
    return
}

How convert identifiers array with pq.Int64Array elements to string where elements of array separated by comma?

Answer 1

Because the type pq.Int64Array is a slice type, the application is scanning to a slice of slices. Scan to a slice only:

var identifiers pq.Int64Array
if err := database.DBSQL.QueryRow(sqlStatement.String()).Scan(&identifiers); err != nil {
    log.Println(err)
    utils.ResponseWithError(responseWriter, http.StatusInternalServerError, err.Error())
    return
}

Convert each id to a string and append to a buffer. Insert separators between each id. Convert the buffer to a string when done.

var buf []byte
for i, id := range identifiers {
    if i > 0 {
        buf = append(buf, ',')
    }
    buf = strconv.AppendInt(buf, int64(id), 10)
}
s := string(buf)