res = Booking.objects.filter()
# 方法一：exists()
if res.exists():
print('queryset has data')
else:
print('queryset has no data')
# 方法二：count() ==0
if res.count() == 0:
print('empty')
# 方法三：
if res:
print('queryset has data')
else:
print('queryset has no data')
总之，queryset.exists() > queryset.count() > queryset
性能比是exists()最佳，而直接用queryset来判断是最差
标签：count,exists,res,queryset,查询,data,print,django,优化 From： https://www.cnblogs.com/shaoyishi/p/17263119.html