Question

与此Receive range of dates. If starting dating doesn't exist fetch range from the closest past date相关，我遇到了一个奇怪的问题。

这里的表HistoryPrices是这样的：

|    Date    | Price |
|------------|-------|
| 2015-12-25 |  44.5 |
| 2016-01-01 |  90.5 |
| 2016-01-03 |  50.5 |
| 2016-01-04 |  45.6 |
| 2016-01-10 | 40.99 |
| 2016-01-15 |  50.5 |
| 2016-01-22 | 50.99 |

当我运行此查询时：

select *
from HistoryPrices
order by `date` desc
limit 1;

我得到了正确的行| 2016-01-22 | 50.99 |。

当我跑这个时：

select '2016-01-22', Price
from HistoryPrices
order by `date` desc
limit 1;

也是正确的预期结果| 2016-01-22 | 50.99 |

这个查询：

select '2016-01-22' as xxx, Price
from HistoryPrices
order by `date` desc
limit 1;

另外| 2016-01-22 | 50.99 |

然而，当我跑这个时：

select '2016-01-22' as `date`, Price
from HistoryPrices
order by `date` desc
limit 1;

我得到了这个结果| 2016-01-22 | 44.5 |。我不知道为什么会这样。也许列别名和列名是相同的date，那么当order by `date`时，mysql不知道怎么做？但我无法证实这一点。

请问有人可以解释一下吗？任何帮助将不胜感激。提前谢谢。

Answer 1

MySQL允许在while True: num = int(input("Enter a positive number to see if it's a prime number: ")) if num > 1: break elif num == 1: print("1 is technically not a prime number.") else: print("Number cannot be negative- try again.") for num1 in range(2,num): div = num%num1 if div == 0: print(num1,"is a divisor of",num,"... stopping.") print(num,"is not a prime number.") sys.exit() else: print(num1,"is NOT a divisor of",num,"... continuing") print(num,"is a prime number!")中引用列别名。如果您需要表名，请对列进行限定：

order by

当列的别名和列的名称相同时，mysql如何排序？

1 个答案: