Question

我可以在mysql中的as语句中使用BETWEEN或类似的东西。

SELECT * FROM status WHERE date BETWEEN CONVERT_TZ('2013-11-01 00:00:00','GMT','UTC') AND CONVERT_TZ('2013-11-07 23:59:59','GMT','UTC') AS firstweek AND date BETWEEN CONVERT_TZ('2013-11-08 00:00:00','GMT','UTC') AND CONVERT_TZ('2013-11-15 23:59:59','GMT','UTC') AS secondweek AND date BETWEEN CONVERT_TZ('2013-11-16 00:00:00','GMT','UTC') AND CONVERT_TZ('2013-11-22 23:59:59','GMT','UTC') AS secondweek ORDER BY date DESC

我收到语法错误。如何使用BETWEEN使用别名？是否有其他方式每周命名，这将作为我的标识符。

Answer 1

您正在为表达式添加别名，而不是选定列你应该这样做：

SELECT t.* FROM  
(SELECT s.*, CONVERT(...) as field1, CONVERT(...) as field2 from status) t
...then do what you want with fieldsXX...

Answer 2

你可以尝试

SELECT * FROM date JOIN
    (SELECT CONVERT_TZ('2013-11-01 00:00:00','GMT','UTC') AS w1start,
            CONVERT_TZ('2013-11-07 23:59:59','GMT','UTC') AS w1end,
            CONVERT_TZ('2013-11-08 00:00:00','GMT','UTC') AS w2start,
            CONVERT_TZ('2013-11-15 23:59:59','GMT','UTC') AS w2end,
            CONVERT_TZ('2013-11-16 00:00:00','GMT','UTC') AS w3start,
            CONVERT_TZ('2013-11-22 23:59:59','GMT','UTC') AS w3end) AS weeks
    WHERE date BETWEEN w1start AND w1end
       OR date BETWEEN w2start AND w2end
       OR date BETWEEN w3start AND w3end
    ORDER BY date DESC

这至少是一个开始。

但是，如果您想告诉应用程序满足3个条件中的哪个条件，那么yiu可能会想要

SELECT date BETWEEN w1start AND w1end AS firstweek, 
       date BETWEEN w2start AND w2end AS secondweek,
       date BETWEEN w3start AND w3end AS thirdweek,
       whatevercolumsyouneed
       FROM date JOIN
    (SELECT CONVERT_TZ('2013-11-01 00:00:00','GMT','UTC') AS w1start,
            CONVERT_TZ('2013-11-07 23:59:59','GMT','UTC') AS w1end,
            CONVERT_TZ('2013-11-08 00:00:00','GMT','UTC') AS w2start,
            CONVERT_TZ('2013-11-15 23:59:59','GMT','UTC') AS w2end,
            CONVERT_TZ('2013-11-16 00:00:00','GMT','UTC') AS w3start,
            CONVERT_TZ('2013-11-22 23:59:59','GMT','UTC') AS w3end) AS weeks
    HAVING firstweek OR secondweek OR thirdweek
    ORDER BY date DESC

（未经测试;我不确定HAVING是否放置正确。）

Answer 3

您在AS子句中使用WHERE。它只能在列列表和FROM子句中使用。

SELECT a.somefield AS s, someexpr AS e
  FROM table1 AS a, ...
  WHERE ...

我可以在MySQL的'BETWEEN'语句中使用'AS'吗？

3 个答案: