I have this Go code:
package main
import (
"fmt"
"database/sql"
_"github.com/go-sql-driver/mysql"
"time"
)
type User struct {
id uint32
name string
email string
rating uint8
subscription uint8
date_registered time.Time
online string
}
// main entry point
func main() {
// setup db connection
db, err := sql.Open("mysql", "user:@tcp(127.0.0.1:3306)/c9?parseTime=true")
if err != nil {
fmt.Println(err)
}
defer db.Close()
// query
rows, err := db.Query("SELECT * FROM users WHERE id = ?", 1)
if err != nil {
fmt.Println(err)
}
defer rows.Close()
usr := User{}
for rows.Next() {
err := rows.Scan(&usr.id, &usr.name, &usr.email, &usr.rating, &usr.subscription, &usr.date_registered, &usr.online)
if err != nil {
fmt.Println(err)
}
}
fmt.Println(usr)
err = rows.Err()
if err != nil {
fmt.Println(err)
}
}
This is what I get from MySQL console:
mysql> describe users;
+-----------------+---------------------+------+-----+-------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------------+---------------------+------+-----+-------------------+----------------+
| id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| name | varchar(50) | NO | | NULL | |
| email | varchar(50) | NO | | NULL | |
| rating | tinyint(3) unsigned | YES | | NULL | |
| subscription | tinyint(3) unsigned | NO | | 0 | |
| date_registered | timestamp | NO | | CURRENT_TIMESTAMP | |
| online | char(1) | NO | | N | |
+-----------------+---------------------+------+-----+-------------------+----------------+
7 rows in set (0.00 sec)
mysql> SELECT * FROM users;
+----+------------+-----------------------+--------+--------------+---------------------+--------+
| id | name | email | rating | subscription | date_registered | online |
+----+------------+-----------------------+--------+--------------+---------------------+--------+
| 1 | alakhazamm | abcdefghhhh@gmail.com | NULL | 0 | 2014-10-28 15:37:44 | N |
+----+------------+-----------------------+--------+--------------+---------------------+--------+
1 row in set (0.00 sec)
After .Scan(), fmt.Println(usr) prints
{1 alakhazamm abcdefghhhh@gmail.com 0 0 {0 0 <nil>} }
The last two fields of the struct are wrong but I have no idea why. I've tried using date_registered string in the struct definition, but I get an empty string after .Scan(). I've also read in the driver's docs that ?parseTime=true parses MySQL DATE and DATETIME values into time.Time, but they don't mention TIMESTAMP which is what I'm currently using.
Am I missing something important or is it a bug/missing feature of the library?
I've found the cause of the error.
Since rating is NULL in the database, the scanner gave the error
sql: Scan error on column index 3: converting string "nil" to a uint8: strconv.ParseUint: parsing "nil": invalid syntax
I've updated the database row and now usr.date_registered and usr.online hold the correct values.
I guess I'll have to make the MySQL field NOT NULL and just use -1 to indicate a non-initialised value.
I know this is an old question however I was missing this parameter in my Open call:
parseTime=true