计算每行的唯一值（在索引轴上，而不是列方向）

我有下表：

WITH data AS (
SELECT 10 AS A, 10 AS B, 10 AS C
UNION ALL
SELECT 20 AS A, 10 AS B, 20 AS C
UNION ALL
SELECT 30 AS A, 20 AS B, 10 AS C
UNION ALL
SELECT 40 AS A, 40 AS B, 40 AS C
UNION ALL
SELECT 50 AS A, 20 AS B, 20 AS C)

SELECT * FROM data;

    A   B   C
0  10  10  10
1  20  10  20
2  30  20  10
3  40  40  40
4  50  20  20

现在，我想计算每行的唯一值的数量，并将其存储在名为Unique_count

所以我的预期输出将是：

A   B   C  Unique_count
0  10  10  10             1
1  20  10  20             2
2  30  20  10             3
3  40  40  40             1
4  50  20  20             2

我熟悉SELECT DISTINCT。但是这些都是按列操作。我不知道如何在SQL中对每一行进行计数。

使用pandasPython中的模块，它将简单地是：

data['Unique_count'] = data.nunique(axis=1)

我有机会获得一个MS SQL SERVER或者MySQL SERVER所以在这两种方言的答案被接受。