Select SUM(Breakfast) FROM `expense` WHERE MONTHNAME(Date)='February'
Select (BreakFast+lunch+dinner) as Total FROM `expense` WHERE Date='2016-01-01'
合并结果取决于条件。查询合并两个结果取决于条件
SUM(Breakfast)
如果是2月份,应该选择。
如果不是意味着
(BreakFast+lunch+dinner) as Total
必须加油特定日期。
我尝试了联盟,但我没有得到期望的结果
Table expense
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Date Breakfast Lunch Dinner
2016-02-02 20 20 30
2016-02-03 30 30 20
2016-01-02 40 30 20 90(If It is a month Of Not a Feb)
50(If It is a month Of Feb)
--------------------------
的MySQL或SQL Server?你已经标记了他们两个。 – Fred
不知道问题是什么。 – shawnt00