Question

我知道这有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：

声明1

SELECT COUNT(softwareone) AS totalcount 
FROM my_table WHERE softwareone LIKE '%typeone%'

totalcount = 3 _

声明2

SELECT COUNT(softwaretwo) AS totalcount 
FROM my_table WHERE softwaretwo LIKE '%typeone%'

totalcout = 1

我想将两个总和相加得到totalcount = 4.还有办法吗？

注意：“softwareone”和“softwaretwo”列中的软件类型属于同一类型（相同值）。

感谢所有人。

Answer 1

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%'
;

当满足两个条件时，CASE ... END表达式将评估为2（如果softwareone和softwaretwo都是LIKE '%typeone%'，那么行计数两次），1只有其中一个。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行总数。

Answer 2

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

MySQL总和两个COUNT语句

2 个答案: