Mysql SQL按列搜索'；s内容，并让列名位于结果表的第一列

如果我有一个表，并希望搜索每个列的内容：

name    col1    col2
data1   1       10
data2   2       20
data3   na      30
data4   4       na
data5   5       na
...     ...     ...

我想得到如下表格：

col_name    na    not_na
col1        1     4
col2        2     3

有什么方法可以做到这一点吗？ 首先谢谢

你可以做一个联盟

(
    SELECT 'col1' as col_name,
    (SELECT COUNT(`name`) FROM `table` WHERE `col1` = 'na') as na,
    (SELECT COUNT(`name`) FROM `table` WHERE `col1` != 'na') as not_na
)
UNION
(
    SELECT 'col2' as col_name,
    (SELECT COUNT(`name`) FROM `table` WHERE `col2` = 'na') as na,
    (SELECT COUNT(`name`) FROM `table` WHERE `col2` != 'na') as not_na
)

---

最简单的方法是构造一个

union all

查询：

select 'col1' as column, sum(col1 = 'na') as na,
       sum(col1 is distinct from 'na') as not_na
from t
union all
select 'col2' as column, sum(col2 = 'na') as na,
       sum(col2 is distinct from 'na') as not_na
from t;

---

如果有很多列，则可以使用元数据表上的查询（

信息_SCHEMA

）或电子表格来构造此类查询。

使用包含If:

SELECT 
    'col1' as `col_name`,
    SUM(IF(`col1` = 'na',1,0)) as `na`,
    SUM(IF(`col1` = 'na',0,1)) as `not_na`
FROM `table`
UNION
SELECT 
    'col2' as `col_name`,
    SUM(IF(`col2` = 'na',1,0)) as `na`,
    SUM(IF(`col2` = 'na',0,1)) as `not_na`
FROM `table`;

---

我不太明白你的意思。。输入是如何转换的？@Teja看起来输出是具有该值的行的计数。我弄乱并编辑了你的答案，而不是添加我自己的答案。请原谅我的错误，把你的答案放回原处。我道歉@懒汉。没有造成伤害。我以前也这么做过。