Question

我有一个这样的表：

| name    |  salary |  day  |  month   |
| james   |  200.00 |    2  | january  |
| marie   |  400.00 |    4  | january  |
| jimmy   |  300.00 |    7  | january  |
| Fredd   |  700.00 |    3  | february |
| rosieli |  500.00 |    5  | february |
| rosela  |  800.00 |    6  | february |

如果表名是'db_table'，我该如何编写sql select查询来选择1月4日至2月5日的记录。
像这样：

select * from db_table between day='4',month='january' and day='5' and month='february'";

请我如何编写适当的sql语句以获得所需的结果。以使表如下所示：

| name    |  salary |  day  |  month   | 
| marie   |  400.00 |    4  | january  |
| jimmy   |  300.00 |    7  | january  |
| Fredd   |  700.00 |    3  | february |
| rosieli |  500.00 |    5  | february |

谢谢

Answer 1

您需要将日期设为数字，但这就是它：

SELECT *
FROM db_table
WHERE (day >= 4 and month = 'January')
   OR (day <= 5 and month = 'February')

例如一月至四月：

SELECT *
FROM db_table
WHERE (day >= 4 and month = 'January')
   OR (day <= 5 and month = 'April')
   OR month IN ('February','March')

Answer 2

您必须在month语句中使用day和between创建一个可比较的字符串：

select * from db_table where 
concat(case month 
         when 'january' then '01'
         when 'february' then '02'
         ........................
         when 'december' then '12'
       end, case when day < 10 then '0' else '' end, day) between '0104' and '0205'

像这样，您可以通过仅修改开始日期和结束日期来比较任何日期范围。

Answer 3

我该如何编写sql select查询来选择1月4日至2月5日的记录。

select  *
from    db_table
where   (month = 'january' and 4 <= cast(day as int)) or
        (month = 'february' and cast(day as int) <= 5)

请注意，具有单独的月份和日期列的表设计使查询变得困难。在年份的界限上将变得更加困难。更好的设计将利用数据库的本机datetime列类型。然后您可以像这样查询：

select  *
from    db_table
where   dt_col between '2019-01-04' and '2019-02-05'

Answer 4

您确实应该使用日期。

select t.*
from t
where str_to_date(concat_ws(2020, month, day), '%Y %M %d') between '2020-01-04' and '2020-02-05';

在可能的情况下，应该使用日期进行日期比较。

我使用2020是因为它是a年，所以它将处理2月29日。

解决此问题后，应修复数据模型以包含实际日期，而不是月/日组合。

多SQL选择语句

4 个答案: