mysql - 在 SQL 中计算相同的行值作为一个

Question

我有一张这样的 table :

Id     Subdistrict   District
-----------------------------
1      K             S
2      K             S
3      M             S
4      J             B
5      J             B

如果相同的分区(以及分区)值将计为 1，我希望它返回这样的结果:

Subdistrict = 3 (Because there are only K, M, and J Subdistrict)

District = 2 (Because there are only S and B District)

如何编写sql查询？提前致谢:)

Answer 1

• 使用Count function with Distinct , 计算字段的唯一行数(非空值)。

尝试以下查询:

SELECT COUNT(DISTINCT Subdistrict) AS number_of_subdistricts, 
       COUNT(DISTINCT District) AS number_of_districts 
FROM your_table