如何使用COUNT和WHERE MySQL查询多个colums结合

Question

所以我想通了如何生成一个报告，其中将数项基于WHERE条件一样每个月：

SELECT 
    Year(FROM_UNIXTIME(`tTime1`)) as YEAR, 
    Month(FROM_UNIXTIME(`tTime1`)) as MONTH, 
    Count(*) As BUY_RESULT 
    FROM zupsbackup 
    WHERE Result='BUY' AND tPeriod='60' 
    GROUP BY Year(FROM_UNIXTIME(`tTime1`)), Month(FROM_UNIXTIME(`tTime1`)) 

这将产生表结果如

YEAR|MONTH|BUY_RESULT 

但是，我的结果列有2个可能的值买入和卖出。

所以我想另一列添加到结果，这样它看起来像

YEAR|MONTH|BUY_RESULT|SELL_RESULT 

我怎样才能在MySQL中建立另一列???

我已经试过UNION但是这增加了卖出的结果，以结果表的末尾，不创建额外的列。

那么，如何创建使用WHERE子句，从而导致一个额外的列=“卖”被旁边的现有列，其中RESULT =“买入”添加?????

谢谢!!!!!

Answer 1

使用条件汇总：

SELECT Year(FROM_UNIXTIME(`tTime1`)) as YEAR, Month(FROM_UNIXTIME(`tTime1`)) as MONTH, 
     SUM(Result = 'BUY') As BUY_RESULT, SUM(Result = 'SELL') as SELL_RESULT 
FROM zupsbackup 
WHERE tPeriod = '60' 
GROUP BY Year(FROM_UNIXTIME(`tTime1`)), Month(FROM_UNIXTIME(`tTime1`)); 

Answer 2

一个简单的方法来完成，这是使用子查询：

SELECT 
    Year(FROM_UNIXTIME(tTime1)) as YEAR, 
    Month(FROM_UNIXTIME(tTime1)) as MONTH, 
    Count(*) As BUY_RESULT, 
    (
    SELECT 
     COUNT(sub.*) 
    FROM 
     zupsbackup AS sub 
    WHERE 
     sub.Result = 'SELL' and 
     sub.tPeriod = '60' AND 
     Year(FROM_UNIXTIME(sub.tTime1)) = YEAR AND 
     Month(FROM_UNIXTIME(tTime1)) = MONTH 
) AS SELL_RESULT 
FROM 
    zupsbackup 
WHERE 
    Result='BUY' AND 
    tPeriod='60' 
GROUP BY 
    Year(FROM_UNIXTIME(tTime1)), 
    Month(FROM_UNIXTIME(tTime1))