從字符串中獲取數據字符串整型數據類型

Question

我想從日期和時間獲取總和（成本）的數據。我的表字段的數據類型是id是INT AUTO INCREMENT，dd是varchar，mm是varchar，yyyy varchar和dd值是01到31，mm值是01到12，年值是4位數年份（2016或2015 ... ） 正是我想要總和（成本）= 143

SELECT SUM(cost) FROM costing 
WHERE 
    ((dd> CAST('05' AS SIGNED) AND mm= CAST('12' AS SIGNED) AND yyyy= CAST('2015' AS SIGNED)) 
    AND 
    ((dd<= CAST('23' AS SIGNED) AND mm = CAST('01' AS SIGNED) AND yyyy= CAST('2016' AS SIGNED))) 

    order by id 

Answer 1

您可以使用CAST AS DATE函數是這樣的：

SELECT 
    SUM(cost) FROM costing 
WHERE 
    CAST(CONCAT(yyyy,mm,dd) AS DATE) BETWEEN '2015-12-05' AND '2016-01-23' 

Answer 2

首先，你應該考慮你的數據類型。日期不應以varchar或整數數據類型。請參考此http://www.w3schools.com/sql/sql_datatypes.asp

然後你可以使用之間。請參考此http://www.w3schools.com/sql/sql_between.asp

然後，您在您的查詢中不需要order by id。

您的查詢會喜歡 SELECT SUM(cost) FROM costing WHERE costingdate BETWEEN "5-12-2015" AND 23-1-2015"