Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

1.9.2

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

win10 X64 i7 7700HQ

What did you do?

I called a sql server 2012sp3 's proc with output param as the sql.Out example shows
as below:

var strErrorDescribe string
	_, err = db.GetmyssqlDB().ExecContext(context.Background(), "NET_PW_InsureIn",
		sql.Named("dwUserID", m.UserId),
		sql.Named("dwScore", m.MoneyAmount),
		sql.Named("strErrorDescribe", sql.Out{Dest: &strErrorDescribe}))

strErrorDescribe is the NVARCHAR(127) OUTPUT param
but i got err as "unsupported type from server string=存款成功!"
and the 'strErrorDescribe' returned value is ""

What did you expect to see?

strErrorDescribe should contain 存款成功 as returned value

What did you see instead?

the 'strErrorDescribe' returned value is ""