新增：完善withdraw的返回值

tools/utils.go

@@ -1,6 +1,7 @@
 package tools
 
 import (
+	"database/sql"
 	"encoding/json"
 	"fmt"
 	"strings"
@@ -144,3 +145,16 @@ func NullDecimalToString(d decimal.NullDecimal, precision ...int32) *string {
 	}
 	return lo.ToPtr(d.Decimal.StringFixedBank(precision[0]))
 }
+
+//将sql.NullTime转换为*string
+func NullTime2PointerString(nullTime sql.NullTime) *string {
+	var strPtr *string
+	if nullTime.Valid {
+		str := nullTime.Time.String()
+		strPtr = &str
+		return strPtr
+	} else {
+		strPtr = nil
+		return strPtr
+	}
+}