MySQL两个COUNT语句之和

我知道这是一个愚蠢的解决方案，但是，对不起，我有点困惑

我有两个SELECT COUNT语句。例如：

报表1

总数=3 _

报表2

totalcout=1

我想将两个总数相加，得到totalcount=4。有办法吗

注：“软件一号”和“软件二号”列中的软件类型相同（值相同）

感谢大家。

一种方法是写：

SELECT SUM(CASE WHEN softwareone LIKE '%typeone%'
                 AND softwaretwo LIKE '%typeone%'
                THEN 2
                ELSE 1
            END
          ) AS "totalcount"
  FROM my_table
 WHERE softwareone LIKE '%typeone%'
    OR softwaretwo LIKE '%typeone%'
;

案例。。。END

表达式在两个条件都满足时将计算为

2

（因此，如果

softwareone

和

softwaretwo

都是

类似“%typeone%”

，则行计数两次），并且在只有一个条件满足时计算为

1

。因此，

SUM（CASE…END）

给出满足一个条件的总行数，加上满足另一个条件的总行数。

您可以使用

Select l1.totalcount + l2.totalcount FROM 
(SELECT COUNT(softwareone) AS totalcount 
FROM my_table WHERE softwareone LIKE '%typeone%') as l1,
(SELECT COUNT(softwaretwo) AS totalcount 
FROM my_table WHERE softwaretwo LIKE '%typeone%') as l2

---

这两个选项都是故意在

%typeone%

上选择filter的吗？+1子查询解决方案会导致MySQL多次扫描记录。此查询只会导致MySQL扫描一次。

SELECT SUM(CASE WHEN softwareone LIKE '%typeone%'
                 AND softwaretwo LIKE '%typeone%'
                THEN 2
                ELSE 1
            END
          ) AS "totalcount"
  FROM my_table
 WHERE softwareone LIKE '%typeone%'
    OR softwaretwo LIKE '%typeone%'
;

Select l1.totalcount + l2.totalcount FROM 
(SELECT COUNT(softwareone) AS totalcount 
FROM my_table WHERE softwareone LIKE '%typeone%') as l1,
(SELECT COUNT(softwaretwo) AS totalcount 
FROM my_table WHERE softwaretwo LIKE '%typeone%') as l2