英文:
How to parse time from database
问题
我正在使用golang，尝试从MySQL中读取时间，但是遇到了以下错误。
var my_time time.Time
rows, err := db.Query("SELECT current_time FROM table")
err := rows.Scan(&my_time)
我得到的错误是：
unsupported driver -> Scan pair: []uint8 -> *time.Time
我该如何修复这个问题？
英文:
I am using golang and I am trying to read time from mysql and I am getting the following error.
var my_time time.Time
rows, err := db.Query("SELECT current_time FROM table")
err := rows.Scan(&my_time)
The error I am getting is
unsupported driver -> Scan pair: []uint8 -> *time.Time
How can I fix this?
答案1
得分: 78
假设您正在使用go-sql-driver/mysql，您可以要求驱动程序自动将DATE和DATETIME扫描为time.Time，只需在连接字符串中添加parseTime=true。
请参阅https://github.com/go-sql-driver/mysql#timetime-support
示例代码：
db, err := sql.Open("mysql", "root:@/?parseTime=true")
if err != nil {
panic(err.Error()) // 仅作为示例目的。您应该使用适当的错误处理，而不是 panic
}
defer db.Close()
var myTime time.Time
rows, err := db.Query("SELECT current_timestamp()")
if rows.Next() {
if err = rows.Scan(&myTime); err != nil {
panic(err)
}
}
fmt.Println(myTime)
请注意，这适用于current_timestamp，但不适用于current_time。如果您必须使用current_time，则需要自行进行解析。
这是如何进行自定义解析的方法：
首先，我们定义一个包装[]byte的自定义类型，它将自动解析时间值：
type rawTime []byte
func (t rawTime) Time() (time.Time, error) {
return time.Parse("15:04:05", string(t))
}
然后在扫描代码中，我们只需这样做：
var myTime rawTime
rows, err := db.Query("SELECT current_time()")
if rows.Next() {
if err = rows.Scan(&myTime); err != nil {
panic(err)
}
}
fmt.Println(myTime.Time())
英文:
Assuming you're using the go-sql-driver/mysql you can ask the driver to scan DATE and DATETIME automatically to time.Time, by adding parseTime=true to your connection string.
See https://github.com/go-sql-driver/mysql#timetime-support
Example code:
db, err := sql.Open("mysql", "root:@/?parseTime=true")
if err != nil {
panic(err.Error()) // Just for example purpose. You should use proper error handling instead of panic
}
defer db.Close()
var myTime time.Time
rows, err := db.Query("SELECT current_timestamp()")
if rows.Next() {
if err = rows.Scan(&myTime); err != nil {
panic(err)
}
}
fmt.Println(myTime)
Notice that this works with current_timestamp but not with current_time. If you must use current_time you'll need to do the parsing youself.
This is how you do custom parsing:
First, we define a custom type wrapping []byte, that will automatically parse time values:
type rawTime []byte
func (t rawTime) Time() (time.Time, error) {
return time.Parse("15:04:05", string(t))
}
And in the scanning code we just do this:
var myTime rawTime
rows, err := db.Query("SELECT current_time()")
if rows.Next() {
if err = rows.Scan(&myTime); err != nil {
panic(err)
}
}
fmt.Println(myTime.Time())
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