ColumnTypeScanType() returns sql.Null[uint64] for bigint unsigned (#1612)

Co-authored-by: elonnzhang <elonnzhang@tencent.com>
Co-authored-by: Inada Naoki <songofacandy@gmail.com>

Author: 3 people

AUTHORS

@@ -18,8 +18,8 @@ Alex Snast <alexsn at fb.com>
 Alexey Palazhchenko <alexey.palazhchenko at gmail.com>
 Andrew Reid <andrew.reid at tixtrack.com>
 Animesh Ray <mail.rayanimesh at gmail.com>
-Arne Hormann <arnehormann at gmail.com>
 Ariel Mashraki <ariel at mashraki.co.il>
+Arne Hormann <arnehormann at gmail.com>
 Artur Melanchyk <artur.melanchyk@gmail.com>
 Asta Xie <xiemengjun at gmail.com>
 B Lamarche <blam413 at gmail.com>
@@ -65,6 +65,7 @@ Jeff Hodges <jeff at somethingsimilar.com>
 Jeffrey Charles <jeffreycharles at gmail.com>
 Jennifer Purevsuren <jennifer at dolthub.com>
 Jerome Meyer <jxmeyer at gmail.com>
+Jiabin Zhang <jiabin.z at qq.com>
 Jiajia Zhong <zhong2plus at gmail.com>
 Jian Zhen <zhenjl at gmail.com>
 Joe Mann <contact at joemann.co.uk>
@@ -84,10 +85,11 @@ Linh Tran Tuan <linhduonggnu at gmail.com>
 Lion Yang <lion at aosc.xyz>
 Luca Looz <luca.looz92 at gmail.com>
 Lucas Liu <extrafliu at gmail.com>
-Lunny Xiao <xiaolunwen at gmail.com>
 Luke Scott <luke at webconnex.com>
+Lunny Xiao <xiaolunwen at gmail.com>
 Maciej Zimnoch <maciej.zimnoch at codilime.com>
 Michael Woolnough <michael.woolnough at gmail.com>
+Minh Quang <minhquang4334 at gmail.com>
 Nao Yokotsuka <yokotukanao at gmail.com>
 Nathanial Murphy <nathanial.murphy at gmail.com>
 Nicola Peduzzi <thenikso at gmail.com>
@@ -98,7 +100,6 @@ Paul Bonser <misterpib at gmail.com>
 Paulius Lozys <pauliuslozys at gmail.com>
 Peter Schultz <peter.schultz at classmarkets.com>
 Phil Porada <philporada at gmail.com>
-Minh Quang <minhquang4334 at gmail.com>
 Rebecca Chin <rchin at pivotal.io>
 Reed Allman <rdallman10 at gmail.com>
 Richard Wilkes <wilkes at me.com>

fields.go

@@ -128,6 +128,7 @@ var (
 	scanTypeInt64      = reflect.TypeOf(int64(0))
 	scanTypeNullFloat  = reflect.TypeOf(sql.NullFloat64{})
 	scanTypeNullInt    = reflect.TypeOf(sql.NullInt64{})
+	scanTypeNullUint   = reflect.TypeOf(sql.Null[uint64]{})
 	scanTypeNullTime   = reflect.TypeOf(sql.NullTime{})
 	scanTypeUint8      = reflect.TypeOf(uint8(0))
 	scanTypeUint16     = reflect.TypeOf(uint16(0))
@@ -185,6 +186,9 @@ func (mf *mysqlField) scanType() reflect.Type {
 			}
 			return scanTypeInt64
 		}
+		if mf.flags&flagUnsigned != 0 {
+			return scanTypeNullUint
+		}
 		return scanTypeNullInt
 
 	case fieldTypeFloat: